set 2 MCQ Questions & Answers Detailed Explanation

Question : 1

Which of the following pairs is/are correctly matched?

1. Isotopes : Atoms with same atomic number but different atomic mass
2. Isobars : Atoms with same number of neutrons but different atomic number
3. Isotones : Atoms with same mass number but different atomic number

a) 1 and 2 only

b) 1 only

c) 1, 2 and 3

d) 2 only

Question : 2

The cathode ray experiment was done for the first time by

a) John Dalton

b) Goldstein

c) J.J. Thomson

d) Rutherford

Question : 3

Which one of the following is heavy water used in nuclear reactor?

a) Water at 4°C but having molecular weight 19 u

b) Water having molecular weight 20 u

c) Water having molecular weight 18 u

d) Water below the ice in a frozen sea

Question : 4

The atomic weights are expressed in terms of atomic mass unit. Which one of the following is used as a standard?

a) ¹²C₆

b) ¹⁶O₈

c) ¹H₁

d) ³⁵Cl₁₇

Question : 5

Which would be the electrical charge on a sulphur atom containing 18 electrons ?

a) 1–

b) 0

c) 2–

d) 2+

Question : 6

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