Atoms and Molecules

An atom has an atomic number of 15 and a mass number of 31. How many protons are there in the atom?

• 15

• 31

• 16

• 47

Which of the following is not a polyatomic ion?

• Sulphide

• Sulphite

• Sulphate

• Bisulphide

The symbol of Mercury is taken from its latin name:

• Cuprum

• Stibium

• Argentum

• Hydrargyrum

Which of the following is not a postulate of Dalton's Atomic Theory?

• All matter consists of indivisible particles called atoms.

• Atoms cannot be created or destroyed.

• Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements.

• The electron is the smallest unit of matter that can take part in a chemical reaction.

Dalton proposed this atomic symbol for which element?

• Phosphorus

• Sulphur

• Hydrogen

• Mercury

IUPAC stands for:

• International Understanding of Physics and Chemistry

• International Union of Pure and Applied Chemistry

• Indian Union of Pure and Applied Chemistry

• International Union of Permutation and Combination

The volume of atom is about ---------------- times the volume of nucleus

• 10⁵

• 10¹⁰

• 10¹⁵

• 10²⁰

unified mass (u) equals

1 u =

• 1.66 x 10^-24 Kg

• 1.66 x 10^-24 g

• 1.66 x 10^-27 g

• 1.66 x 10^-21 Kg

Mass of 1 mole of ethane (C₂H₆) is

• 30 g

• 30 u

• 30

• None