set 2 MCQ Questions & Answers Detailed Explanation

Question : 1

Molecular mass is defined as the

a) mass of one atom compared with the mass of one atom of hydrogen

b) mass of one molecule of any substance compared with the mass of one atom of C-12

c) mass of one atom compared with the mass of one molecule

d) None of these

Question : 2

The nucleus of a singly ionized carbon atom contains

a) 6 protons, 6 neutrons and 6 electrons

b) 5 protons and 6 neutrons

c) 6 protons and 6 neutrons

d) 12 protons, 6 neutrons and 6 electrons

Question : 3

The following questions consist of two statements, one labelled as the Assertion (A) and the other as 'Reason (R), You are to examine these two statements carefully and select the answers to these items using the codes given below:
Assertion (A) :
Atomic weights of most of the elements are not whole numbers.
Reason (R) :
Atoms of most of the elements contain mixture of isotopes having different atomic weights.

a) A is true but R is false

b) Both A and R are individually true but R is NOT the correct explanation of A

c) Both A and R are individually true and R is the correct explanation of A

d) A is false but R is true

Question : 4

Isotopes are those atoms of the same element which have

a) Atomic mass is different but atomic number is same

b) Atomic number and atoms mass both are same

c) Atomic mass is same but atomic number is different

d) None of the above

Question : 5

The nucleus of an atom contains

a) electrons

b) protons and neutrons

c) protons

d) neutrons

Question : 6

In an atom valence electron are present in

a) next to outermost orbit

b) first orbit

c) outermost orbit

d) any one of its orbit