set 1 MCQ Questions & Answers Detailed Explanation

Question : 1

The molecular formula P₂O₅ means that

a) there are twice as many P atoms in the molecule as there are O atoms

b) the ratio of the mass of P to the mass of O in the molecule is 2:5

c) a molecule contains 2 atoms of P and 5 atoms of O

d) the ratio of the mass of P to the mass of O in the molecule is 5 : 2

Question : 2

By whom was neutron discovered?

a) Chadwick

b) Rutherford

c) Bohr

d) Dalton

Question : 3

Which one among the following statements about an atom is not correct?

a) Atoms are always neutral in nature

b) Atoms are the basic units from which molecules and ions are formed

c) Atoms always combine to form molecules

d) Atoms aggregate in large numbers to form the matter that we can see, feel and touch

Question : 4

The total number of atoms represented by the compound CuSO₄ .5H₂O is

a) 21

b) 5

c) 27

d) 8

Question : 5

In which one of the following is the valence electronic configuration, ns²np³ found ?

a) Nitrogen

b) Oxygen

c) Carbon

d) Argon

Question : 6

Which one of the following statement is not true ?

a) The total number of neutrons and protons is always equal in a neutral atom

b) The total number of electrons and protons in an atom is always equal

c) Most of the space in an atom is empty

d) The total number of electrons in any energy level can be calculated by the formula 2n²