Two elements P and Q with atomic radii 231 pm and 186 pm, respectively,  belong to the same group. If element P belongs to the 4th period  which period does element Q belong to?

Newland law of octave arranged elements in increasing order of

A compound contains 20% hydrogen and 80% carbon (by mass). If the vapour density of the compound is 15, calculate its molecular formula.

Identify the option that represents halogens and their position in the modern periodic table.

Dilute hydrochloric acid reacts with calcium carbonate to produce a gas that turns moist  blue litmus paper red. Identify the gas.

Modern periodic table was given by 

Which of the following salt solution can be used to distinguish between sodium hydroxide and ammonium hydroxide solutions?

Which of the following options is not correct about the anode in an electrolytic cell?

The best oxidising agent among the following elements would be:

An ionic bond is formed between two elements X and Y such that the formula obtained is XY_{3 ,}  determine the total number of electrons transferred from X→Y.

Which of the following elements is not suitable for the manufacture of a container required to store copper sulphate solution?

Horizontal rows of periodic table are called 

Lithium exhibits diagonal relationship with 

Group of elements kept at the bottom of the periodic table is 

The noble gas having electronic configuration 2,8,8

Identify the correct conversion of forms of energy in an electrolytic cell.

Which of the following elements is best suited to be used as a cathode in  an electrolytic cell?

What will be the colour of the precipitate formed when zinc sulphate is treated with excess ammonium hydroxide?

In the periodic table, alkali metals are placed in which group

Which of the following elements does not loose an electron easily?

On moving from left to right in a periodic table the size of an atom 

Select the incorrect statement in terms of ionic and covalent bonds.

Which of the following elements exhibit a diagonal relationship with beryllium?

Dry blue litmus paper turns red in the presence of:

Electrolytic dissociation of AlCl₃ will produce:

A compound of carbon, hydrogen, and nitrogen contains these elements in the ratio 18:2:7. Calculate the empirical formula of the compound.

Which of the following colours correctly denotes the presence of ferric ions  in a solution?

The respective bonds involved in the formation of H₂O and H₃O ⁺ are:

The vapour density of oxygen gas is:

Electronic configuration of an element X having atomic number 24 is 

Study the given reaction: 

2Na(s) + 2HCl(aq) → 2NaCl(aq) + H2 (g)

Identify the most suitable indicator to determine the nature of the product formed.

Determine the oxidation state and valency, respectively, of a sodium atom.

Which of the following metal oxides is not amphoteric in nature?

The atom of an element present in group VA of the modern periodic table contains 3 shells. Find its valency and electronic configuration.

The ionisation energy (in kJ mol -1 ) of some elements is given.

● M → 520

● N → 498

● O → 419

● P → 403

Which of these elements will undergo an oxidation reaction at the fastest rate?

Which of the two groups in the modern periodic table are most likely to form an ionic bond?

How many elements have been discovered till now?

To decrease the chemical reactivity, alkali metals are converted to 

The non-metal in  period 3 having valency 1 is