Before Giving Care - Warm Up

Commas Directions: Correct the sentences by adding commas where needed. 1. After the sound of the bell we realized it was a false alarm. 2. Mr. Yoshino the head of the department resigned yesterday. 3. The gentleman with the black umbrella who is an ambassador to the United States said hello to us as we were entering the hotel. 4. Even though we won the game the players unfortunately did not play their best. 5. Heather walked quickly up to the door and knocked hoping that someone would answer. Author’s Purpose 6. An author writes a story about a boy who saves his town from a flood by using his quick thinking. The author includes exciting descriptions of the boy's bravery. What is the author’s most likely purpose for writing this story? A. To inform readers about the dangers of floods B. To entertain readers with a heroic tale C. To explain how to prevent floods D. To persuade readers to prepare for emergencies 7. Which of the following is an example of an author writing to persuade? A. A science textbook chapter explaining the water cycle B. A commercial encouraging people to adopt shelter pets C. A short story about a girl who finds a magical necklace D. A recipe for making chocolate chip cookies 8. Read the following sentence: "Studies show that students who read for 20 minutes a day score higher on tests. Reading is one of the best habits you can develop for success in school and life." What is the author’s purpose in this passage? A. To entertain readers with a fun story B. To persuade readers to read more often C. To inform readers about how books are written D. To explain how to find books to read 9. An author writes a how-to guide titled 10 Easy Steps to Plant a Garden. What is the author’s primary purpose? A. To persuade readers to grow their own vegetables B. To inform readers how to plant a garden C. To entertain readers with funny garden tips 10. Read the excerpt: "Long ago, in a village surrounded by mountains, the people discovered a secret about their water well. Every full moon, the well water turned to gold for just one night. But no one knew why. This mystery brought travelers from far and wide, hoping to uncover the truth." What is the author’s purpose in this excerpt? A. To persuade readers to visit the village B. To inform readers about a historical event C. To entertain readers with a mysterious tale D. To explain the science behind the water Main Idea When I stepped out into the bright sunlight from the darkness of the movie house, I had only two things on my mind: Paul Newman and a ride home. I was wishing I looked like Paul Newman--- he looks tough and I don't--- but I guess my own looks aren't so bad. I have light-brown, almost-red hair and greenish-gray eyes. I wish they were more gray because I hate most guys that have green eyes, but I have to be content with what I have. My hair is longer than a lot of boys wear theirs, squared off in back and long at the front and sides, but I am a greaser and most of my neighborhood rarely bothers to get a haircut. Besides, I look better with long hair. 11. What is the main idea? The narrator likes movies. The narrator wishes he was Paul Newman. The narrator is content with his appearance. The narrator looks better with long hair. 12. The narrator believes. . . looks are important. he should get a haircut. green eyes are bad. that he has red hair. Once there were four girls who shared a pair of pants. The girls were all different sizes and shapes, and yet the pants fit each of them. You may think this is a suburban myth. But I know it's true, because I am one of them, one of the sisters of the Traveling Pants. We discovered their magic last summer, purely by accident. The four of us were splitting up for the first time in our lives. Carmen had gotten them from a secondhand place without even bothering to try them on. She was going to throw them away, but by chance, Tibby spotted them. First Tibby tried them; then me, Lena; then Bridget; then Carmen. By the time Carmen pulled them on, we knew something extraordinary was happening. If the same pants fit and I mean really fit the four of us, they aren't ordinary. They don't belong completely to the world of things you can see and touch. My sister, Effie, claims I don't believe in magic, and maybe I didn't then. But after the first summer of the Traveling Pants, I do. 13. What is the main idea? Four friends were connected through a special pair of pants. A pair of pants called the Traveling Pants. Carmen finding a pair of pants from a second-hand shop. The girls believing in magic. 14. The narrator included that the pants fit all of them to emphasize how the girls become friends. the girls are different sizes. why the pants are special. where the pants came from. If you are interested in stories with happy endings, you would be better off reading some other book. In this book, not only is there no happy ending, there is no happy beginning and very few happy things in the middle. This is because not very many happy things happened in the lives of the three Baudelaire youngsters. Violet, Klaus, and Sunny Baudelaire were intelligent children, and they were charming, and resourceful, and had pleasant facial features, but they were extremely unlucky, and most everything that happened to them was rife with misfortune, misery, and despair. I'm sorry to tell you this, but that is how the story goes. 15. What is the main idea? description about the story to come. A warning about the story and its sad content. A declaration about the Baudelaire family. A beginning for the end of the story. 16. The narrator believes the reader does not like sad stories. likes stories with happy endings. can’t enjoy the story. will find the story unhappy. 17. Read the following sentence: Of course you can exaggerate your story, but what you say must be based on truth. Which word means the same as exaggerate? repeat reveal overstate increase 18. What is the meaning of the word inaugurated, used in the following sentence: Less than two months after Abraham Lincoln was inaugurated President in 1861, he encountered one of the most difficult tasks ever experienced by a United States leader: civil war. elected by a vote brought into office identified by name viewed as an authority 19. What does the phrase “practice your presentation so much that you could do it in your sleep” suggest in the following sentence: The best advice is to practice your presentation so much that you could do it in your sleep. get plenty of sleep the night before giving a presentation give their presentations in front of a small audience first take advice from their teachers on how to write a presentation memorize their presentations before they give them 20. Read the following sentence: The Phoenix Mars Lander is a NASA spacecraft that landed on the Red Planet in May 2009 to study the history of water and potential for life on the planet. What is another word for potential? existence situation possibility qualification

Translator: Joseph Geni Reviewer: Morton Bast Before March, 2011, I was a photographic retoucher based in New York City. We're pale, gray creatures. We hide in dark, windowless rooms, and generally avoid sunlight. We make skinny models skinnier, perfect skin more perfect, and the impossible possible, and we get criticized in the press all the time, but some of us are actually talented artists with years of experience and a real appreciation for images and photography. On March 11, 2011, I watched from home, as the rest of the world did, as the tragic events unfolded in Japan. Soon after, an organization I volunteer with, All Hands Volunteers, were on the ground, within days, working as part of the response efforts. I, along with hundreds of other volunteers, knew we couldn't just sit at home, so I decided to join them for three weeks. On May the 13th, I made my way to the town of Ōfunato. It's a small fishing town in Iwate Prefecture, about 50,000 people, one of the first that was hit by the wave. The waters here have been recorded at reaching over 24 meters in height, and traveled over two miles inland. As you can imagine, the town had been devastated. We pulled debris from canals and ditches. We cleaned schools. We de-mudded and gutted homes ready for renovation and rehabilitation. We cleared tons and tons of stinking, rotting fish carcasses from the local fish processing plant. We got dirty, and we loved it. For weeks, all the volunteers and locals alike had been finding similar things. They'd been finding photos and photo albums and cameras and SD cards. And everyone was doing the same. They were collecting them up, and handing them in to various places around the different towns for safekeeping. Now, it wasn't until this point that I realized that these photos were such a huge part of the personal loss these people had felt. As they had run from the wave, and for their lives, absolutely everything they had, everything had to be left behind. At the end of my first week there, I found myself helping out in an evacuation center in the town. I was helping clean the onsen, the communal onsen, the huge giant bathtubs. This happened to also be a place in the town where the evacuation center was collecting the photos. This is where people were handing them in, and I was honored that day that they actually trusted me to help them start hand-cleaning them. Now, it was emotional and it was inspiring, and I've always heard about thinking outside the box, but it wasn't until I had actually gotten outside of my box that something happened. As I looked through the photos, there were some were over a hundred years old, some still in the envelope from the processing lab, I couldn't help but think as a retoucher that I could fix that tear and mend that scratch, and I knew hundreds of people who could do the same. So that evening, I just reached out on Facebook and asked a few of them, and by morning the response had been so overwhelming and so positive, I knew we had to give it a go. So we started retouching photos. This was the very first. Not terribly damaged, but where the water had caused that discoloration on the girl's face had to be repaired with such accuracy and delicacy. Otherwise, that little girl isn't going to look like that little girl anymore, and surely that's as tragic as having the photo damaged. (Applause) Over time, more photos came in, thankfully, and more retouchers were needed, and so I reached out again on Facebook and LinkedIn, and within five days, 80 people wanted to help from 12 different countries. Within two weeks, I had 150 people wanting to join in. Within Japan, by July, we'd branched out to the neighboring town of Rikuzentakata, further north to a town called Yamada. Once a week, we would set up our scanning equipment in the temporary photo libraries that had been set up, where people were reclaiming their photos. The older ladies sometimes hadn't seen a scanner before, but within 10 minutes of them finding their lost photo, they could give it to us, have it scanned, uploaded to a cloud server, it would be downloaded by a gaijin, a stranger, somewhere on the other side of the globe, and it'd start being fixed. The time it took, however, to get it back is a completely different story, and it depended obviously on the damage involved. It could take an hour. It could take weeks. It could take months. The kimono in this shot pretty much had to be hand-drawn, or pieced together, picking out the remaining parts of color and detail that the water hadn't damaged. It was very time-consuming. Now, all these photos had been damaged by water, submerged in salt water, covered in bacteria, in sewage, sometimes even in oil, all of which over time is going to continue to damage them, so hand-cleaning them was a huge part of the project. We couldn't retouch the photo unless it was cleaned, dry and reclaimed. Now, we were lucky with our hand-cleaning. We had an amazing local woman who guided us. It's very easy to do more damage to those damaged photos. As my team leader Wynne once said, it's like doing a tattoo on someone. You don't get a chance to mess it up. The lady who brought us these photos was lucky, as far as the photos go. She had started hand-cleaning them herself and stopped when she realized she was doing more damage. She also had duplicates. Areas like her husband and her face, which otherwise would have been completely impossible to fix, we could just put them together in one good photo, and remake the whole photo. When she collected the photos from us, she shared a bit of her story with us. Her photos were found by her husband's colleagues at a local fire department in the debris a long way from where the home had once stood, and they'd recognized him. The day of the tsunami, he'd actually been in charge of making sure the tsunami gates were closed. He had to go towards the water as the sirens sounded. Her two little boys, not so little anymore, but her two boys were both at school, separate schools. One of them got caught up in the water. It took her a week to find them all again and find out that they had all survived. The day I gave her the photos also happened to be her youngest son's 14th birthday. For her, despite all of this, those photos were the perfect gift back to him, something he could look at again, something he remembered from before that wasn't still scarred from that day in March when absolutely everything else in his life had changed or been destroyed. After six months in Japan, 1,100 volunteers had passed through All Hands, hundreds of whom had helped us hand-clean over 135,000 photographs, the large majority — (Applause) — a large majority of which did actually find their home again, importantly. Over five hundred volunteers around the globe helped us get 90 families hundreds of photographs back, fully restored and retouched. During this time, we hadn't really spent more than about a thousand dollars in equipment and materials, most of which was printer inks. We take photos constantly. A photo is a reminder of someone or something, a place, a relationship, a loved one. They're our memory-keepers and our histories, the last thing we would grab and the first thing you'd go back to look for. That's all this project was about, about restoring those little bits of humanity, giving someone that connection back. When a photo like this can be returned to someone like this, it makes a huge difference in the lives of the person receiving it. The project's also made a big difference in the lives of the retouchers. For some of them, it's given them a connection to something bigger, giving something back, using their talents on something other than skinny models and perfect skin. I would like to conclude by reading an email I got from one of them, Cindy, the day I finally got back from Japan after six months. "As I worked, I couldn't help but think about the individuals and the stories represented in the images. One in particular, a photo of women of all ages, from grandmother to little girl, gathered around a baby, struck a chord, because a similar photo from my family, my grandmother and mother, myself, and newborn daughter, hangs on our wall. Across the globe, throughout the ages, our basic needs are just the same, aren't they?" Thank you. (Applause) (Applause)

RPMS Quiz: Quality vs. Efficiency 1. A teacher spends five hours creating a highly interactive digital game for a single 40-minute lesson. This is an example of prioritizing: • A) Quality over Efficiency • B) Efficiency over Quality • C) Administrative Competence • D) Resource Management • Hint: The focus is on high-level engagement, but the time investment is very high. 2. Which of the following best describes "Efficiency" in the context of the RPMS? • A) Submitting all MOVs and reports on or before the deadline with minimal errors. • B) Ensuring 100% of students pass the quarterly examination. • C) Creating the most aesthetically pleasing portfolio in the department. • D) Conducting home visits for every single student in a class of 50. • Hint: Look for the option that emphasizes timeliness and resource use. 3. Using a "template" or a "reusable slide deck" for lesson planning is a strategy to improve: • A) Efficiency • B) Instructional Diversity • C) Subject Matter Mastery • D) Classroom Discipline • Hint: Templates reduce the time spent on repetitive formatting. 4. If a teacher provides detailed, personalized feedback to every student but submits the grades two weeks late, they have achieved: • A) High Quality, Low Efficiency • B) Low Quality, High Efficiency • C) High Quality, High Efficiency • D) Low Quality, Low Efficiency • Hint: The work itself is excellent, but the timing is poor. 5. Which tool improves Efficiency without sacrificing the Quality of assessment data? • A) Automated Google Forms for multiple-choice quizzes. • B) Giving everyone a passing grade to save time on checking. • C) Writing long paragraphs of feedback on 200 paper-based essays. • D) Skipping assessments entirely to finish the syllabus faster. • Hint: Look for a balance where technology handles the "busy work." 6. When discussing Quality in your RPMS portfolio, which "Means of Verification" (MOV) is most appropriate? • A) Sample of student work with constructive teacher comments. • B) A logbook showing you arrived at school at 7:00 AM daily. • C) A certificate for attending a 1-hour webinar. • D) A photo of your organized teacher's cabinet. • Hint: Quality is evidenced by the impact on student learning. 7. The concept of "Doing the right things" (Effectiveness) represents: • A) Quality • B) Efficiency • C) Speed • D) Compliance • Hint: "Doing the right things" is about results; "Doing things right" is about process. 8. How does "Efficiency" help a teacher maintain "Quality" in the long run? • A) It prevents burnout by optimizing workload, leaving energy for creative teaching. • B) It allows the teacher to take more side jobs. • C) It ensures the teacher never has to talk to parents. • D) It proves that the teacher is smarter than their peers. • Hint: Consider the relationship between teacher well-being and performance. 9. If a teacher's RPMS rating for Quality is 5 (Outstanding) but Efficiency is 2 (Fair), what is the most likely reason? • A) The teacher produces excellent work but often misses deadlines. • B) The teacher is very fast but makes many mistakes in their reports. • C) The teacher is both slow and produces poor results. • D) The students are failing despite the teacher being very organized. • Hint: Check the gap between the high-standard output and the slow delivery. 10. What is the ultimate goal of balancing Quality and Efficiency in the PPST-RPMS? • A) To achieve sustainable professional excellence that benefits the learners. • B) To get a higher salary increase only. • C) To impress the School Head during the observation. • D) To finish the school year with the least amount of work possible. • Hint: It's about long-term growth for both teacher and student. ________________________________________ Answer Key: 1. A | 2. A | 3. A | 4. A | 5. A | 6. A | 7. A | 8. A | 9. A | 10. A ________________________________________

During the American Revolution, the Founding Fathers met to develop a government that would take over as soon as the British left. By 1777, they had written the Articles of Confederation, which created the first United States government. Under the Articles, the states joined together in an alliance of separate state powers with a very weak central government. For example, the government could not collect taxes or keep a standing military. After ten years, the Founding Fathers realized the Articles created a government that was too weak to work! They decided it was time for a change. The Founding Fathers wanted a stronger government that had more authority with the states. Representatives from each state gathered in Philadelphia on May 14, 1787 to discuss possible changes. They agreed on a federalist government, where a central power would oversee and share authority with the states. To make sure the federal government did not gain too much power, they created three branches to provide for checks and balances. The legislative branch would make the laws, the judicial branch would interpret the laws, and the executive branch would enforce the laws. This solved many problems, but one large issue remained: how would the states be represented in this new federal government? At first, the bigger states wanted the population of a state to determine the amount of representation. But the smaller states called foul! The bigger states would end up deciding the laws for everyone. The smaller states suggested that each state have an equal number of representatives. But that would end up giving smaller states too much power. Finally delegates from Connecticut submitted a solution: Why not have two houses make up the legislative branch? The Senate would have an equal number of representatives from each state. Representation in the House of Representatives would be based on the state’s population. This model is called bicameral representation and helped the delegates find a compromise. Between May and September 1787, the delegates at the Constitutional Convention compromised on many issues in order to unite and build a strong national government. They decided the office of the executive would consist of one person and that the national government would have the power to tax and to create a military. These decisions determined that the new federal government would have more authority than before. Some delegates disagreed with the new system, but many of their concerns would be addressed when the Bill of Rights was added to the Constitution in 1789. Looking Ahead At the end of the Constitutional Convention, the delegates signed the Constitution. Many saw a bright future ahead for the United States. The document guarantees a government with three branches based on a system of checks and balances. The delegates of the Convention successfully created a government that addressed the needs of small and large states alike, while providing for a federal government that would tie them together.

Covalent Molecules and Compounds Just as an atom is the simplest unit that has the fundamental chemical properties of an element, a molecule is the simplest unit that has the fundamental chemical properties of a covalent compound. Some pure elements exist as covalent molecules. Hydrogen, nitrogen, oxygen, and the halogens occur naturally as the diatomic (“two atoms”) molecules H2, N2, O2, F2, Cl2, Br2, and I2 (part (a) in Figure 3.1.1). Similarly, a few pure elements exist as polyatomic (“many atoms”) molecules, such as elemental phosphorus and sulfur, which occur as P4 and S8 (part (b) in Figure 3.1.1). Each covalent compound is represented by a molecular formula, which gives the atomic symbol for each component element, in a prescribed order, accompanied by a subscript indicating the number of atoms of that element in the molecule. The subscript is written only if the number of atoms is greater than 1. For example, water, with two hydrogen atoms and one oxygen atom per molecule, is written as H2O. Similarly, carbon dioxide, which contains one carbon atom and two oxygen atoms in each molecule, is written as CO2. Covalent compounds that predominantly contain carbon and hydrogen are called organic compounds. The convention for representing the formulas of organic compounds is to write carbon first, followed by hydrogen and then any other elements in alphabetical order (e.g., CH4O is methyl alcohol, a fuel). Compounds that consist primarily of elements other than carbon and hydrogen are called inorganic compounds; they include both covalent and ionic compounds. In inorganic compounds, the component elements are listed beginning with the one farthest to the left in the periodic table, as in CO2 or SF6. Those in the same group are listed beginning with the lower element and working up, as in ClF. By convention, however, when an inorganic compound contains both hydrogen and an element from groups 13–15, hydrogen is usually listed last in the formula. Examples are ammonia (NH3) and silane (SiH4). Compounds such as water, whose compositions were established long before this convention was adopted, are always written with hydrogen first: Water is always written as H2O, not OH2. The conventions for inorganic acids, such as hydrochloric acid (HCl) and sulfuric acid (H2SO4), are described elswhere. Note! For organic compounds: write C first, then H, and then the other elements in alphabetical order. For molecular inorganic compounds: start with the element at far left in the periodic table; list elements in same group beginning with the lower element and working up. Write the molecular formula of each compound. a. The phosphorus-sulfur compound that is responsible for the ignition of so-called strike anywhere matches has 4 phosphorus atoms and 3 sulfur atoms per molecule. b. Ethyl alcohol, the alcohol of alcoholic beverages, has 1 oxygen atom, 2 carbon atoms, and 6 hydrogen atoms per molecule. c. Freon-11, once widely used in automobile air conditioners and implicated in damage to the ozone layer, has 1 carbon atom, 3 chlorine atoms, and 1 fluorine atom per molecule. Solution: a. • A The molecule has 4 phosphorus atoms and 3 sulfur atoms. Because the compound does not contain mostly carbon and hydrogen, it is inorganic. • B Phosphorus is in group 15, and sulfur is in group 16. Because phosphorus is to the left of sulfur, it is written first. • C Writing the number of each kind of atom as a right-hand subscript gives P4S3 as the molecular formula. b. • A Ethyl alcohol contains predominantly carbon and hydrogen, so it is an organic compound. • B The formula for an organic compound is written with the number of carbon atoms first, the number of hydrogen atoms next, and the other atoms in alphabetical order: CHO. • C Adding subscripts gives the molecular formula C2H6O. c. • A Freon-11 contains carbon, chlorine, and fluorine. It can be viewed as either an inorganic compound or an organic compound (in which fluorine has replaced hydrogen). The formula for Freon-11 can therefore be written using either of the two conventions. • B According to the convention for inorganic compounds, carbon is written first because it is farther left in the periodic table. Fluorine and chlorine are in the same group, so they are listed beginning with the lower element and working up: CClF. Adding subscripts gives the molecular formula CCl3F. • C We obtain the same formula for Freon-11 using the convention for organic compounds. The number of carbon atoms is written first, followed by the number of hydrogen atoms (zero) and then the other elements in alphabetical order, also giving CCl3F. Write the molecular formula for each compound. a. Nitrous oxide, also called “laughing gas,” has 2 nitrogen atoms and 1 oxygen atom per molecule. Nitrous oxide is used as a mild anesthetic for minor surgery and as the propellant in cans of whipped cream. b. Sucrose, also known as cane sugar, has 12 carbon atoms, 11 oxygen atoms, and 22 hydrogen atoms. c. Sulfur hexafluoride, a gas used to pressurize “unpressurized” tennis balls and as a coolant in nuclear reactors, has 6 fluorine atoms and 1 sulfur atom per molecule. Answer: a. N2O b. C12H22O11 c. SF6. Ionic Compounds The substances described in the preceding discussion are composed of molecules that are electrically neutral; that is, the number of positively-charged protons in the nucleus is equal to the number of negatively-charged electrons. In contrast, ions are atoms or assemblies of atoms that have a net electrical charge. Ions that contain fewer electrons than protons have a net positive charge and are called cations. Conversely, ions that contain more electrons than protons have a net negative charge and are called anions. Ionic compounds contain both cations and anions in a ratio that results in no net electrical charge. Note! Ionic compounds contain both cations and anions in a ratio that results in zero electrical charge.An ionic compound that contains only two elements, one present as a cation and one as an anion, is called a binary ionic compound. One example is MgCl2, a coagulant used in the preparation of tofu from soybeans. For binary ionic compounds, the subscripts in the empirical formula can also be obtained by crossing charges: use the absolute value of the charge on one ion as the subscript for the other ion. This method is shown schematically as follows: Crossing charges. One method for obtaining subscripts in the empirical formula is by crossing charges. When crossing charges, it is sometimes necessary to reduce the subscripts to their simplest ratio to write the empirical formula. Consider, for example, the compound formed by Mg2+ and O2−. Using the absolute values of the charges on the ions as subscripts gives the formula Mg2O2:Polyatomic Ions Polyatomic ions are groups of atoms that bear net electrical charges, although the atoms in a polyatomic ion are held together by the same covalent bonds that hold atoms together in molecules. Just as there are many more kinds of molecules than simple elements, there are many more kinds of polyatomic ions than monatomic ions. Two examples of polyatomic cations are the ammonium (NH4+) and the methylammonium (CH3NH3+) ions. P. The method used to predict the empirical formulas for ionic compounds that contain monatomic ions can also be used for compounds that contain polyatomic ions. The overall charge on the cations must balance the overall charge on the anions in the formula unit. Thus, K+ and NO3− ions combine in a 1:1 ratio to form KNO3 (potassium nitrate or saltpeter), a major ingredient in black gunpowder. Similarly, Ca2+ and SO42− form CaSO4 (calcium sulfate), which combines with varying amounts of water to form gypsum and plaster of Paris. The polyatomic ions NH4+ and NO3− form NH4NO3 (ammonium nitrate), a widely used fertilizer and, in the wrong hands, an explosive. One example of a compound in which the ions have charges of different magnitudes is calcium phosphate, which is composed of Ca2+ and PO43− ions; it is a major component of bones. The compound is electrically neutral because the ions combine in a ratio of three Ca2+ ions [3(+2) = +6] for every two ions [2(−3) = −6], giving an empirical formula of Ca3(PO4)2; the parentheses around PO4 in the empirical formula indicate that it is a polyatomic ion. Writing the formula for calcium phosphate as Ca3P2O8 gives the correct number of each atom in the formula unit, but it obscures the fact that the compound contains readily identifiable PO43− ions.Summary • There are two fundamentally different kinds of chemical bonds (covalent and ionic) that cause substances to have very different properties. • The composition of a compound is represented by an empirical or molecular formula, each consisting of at least one formula unit.Contributors The atoms in chemical compounds are held together by attractive electrostatic interactions known as chemical bonds. Ionic compounds contain positively and negatively charged ions in a ratio that results in an overall charge of zero. The ions are held together in a regular spatial arrangement by electrostatic forces. Most covalent compounds consist of molecules, groups of atoms in which one or more pairs of electrons are shared by at least two atoms to form a covalent bond. The atoms in molecules are held together by the electrostatic attraction between the positively charged nuclei of the bonded atoms and the negatively charged electrons shared by the nuclei. The molecular formula of a covalent compound gives the types and numbers of atoms present. Compounds that contain predominantly carbon and hydrogen are called organic compounds, whereas compounds that consist primarily of elements other than carbon and hydrogen are inorganic compounds. Diatomic molecules contain two atoms, and polyatomic molecules contain more than two. A structural formula indicates the composition and approximate structure and shape of a molecule. Single bonds, double bonds, and triple bonds are covalent bonds in which one, two, and three pairs of electrons, respectively, are shared between two bonded atoms. Atoms or groups of atoms that possess a net electrical charge are called ions; they can have either a positive charge (cations) or a negative charge (anions). Ions can consist of one atom (monatomic ions) or several (polyatomic ions). The charges on monatomic ions of most main group elements can be predicted from the location of the element in the periodic table. Ionic compounds usually form hard crystalline solids with high melting points. Covalent molecular compounds, in contrast, consist of discrete molecules held together by weak intermolecular forces and can be gases, liquids, or solids at room temperature and pressure. An empirical formula gives the relative numbers of atoms of the elements in a compound, reduced to the lowest whole numbers. The formula unit is the absolute grouping represented by the empirical formula of a compound, either ionic or covalent. Empirical formulas are particularly useful for describing the composition of ionic compounds, which do not contain readily identifiable molecules. Some ionic compounds occur as hydrates, which contain specific ratios of loosely bound water molecules called waters of hydration.

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