element or compound that cannot be broken down into simpler components and maintain the properties of the original substance

substance with atoms that are all alike

a substance in which the atoms of two or more elements are combined in a fixed proportion

substance in which its different components are easily distinguished

homogeneous mixture, remains constantly and uniformly mixed and has particles that are so small they cannot be seen with a microscope

heterogeneous mixture whose particles never settle

substance containing two or more components that are blended uniformly so that individual components are indistinguishable with a microscope

heterogeneous mixture containing a liquid, and in which visible particles slowly settle due to gravity

any characteristic of a material, such as size or shape, that you can observe or attempt to observe without changing the identity of the material

any change in size, shape, or state of matter in which the identity of the substance remains the same

any characteristic of a substance, such as flammability, that indicates whether it can undergo a certain chemical change

a change in one substance to a new substance

states that the mass of all substances present before a chemical change equals the mass of all the substances remaining after the change

the smallest particle of an element that retains all the properties of that element

the small, positively charged center of the atom, contains the protons and neutrons

particle in the nucleus with an electric charge of 1+

electrically neutral particle inside the nucleus of an atom

particle with an electric charge of 1-, surrounds the nucleus of an atom

area around the nucleus of an atom where the atom's electrons are most likely to be found

number of protons in the atom's nucleus

weighted average-mass of an element's isotopes according to their natural abundance

atom of an element that has a specific number of neutrons

organized list of all known elements that are arranged by increasing atomic number and by changes in chemical and physical properties

horizontal row in the periodic table

vertical column in the periodic table

uses the symbol for an element and dots representing the number of electrons in the element's outer energy level