set 2 MCQ Questions & Answers Detailed Explanation

Question : 1

Which of the following is a fundamental element?

a) Sand

b) Marble

c) Diamond

d) Sugar

Question : 2

Assertion (A):
In the periodic table of chemical elements, electron affinity is always found to increase from top to bottom in a group.
Reason (R):
In a group, the atomic radii generally increase from top to bottom.

a) Both (A) and (R) are true and (R) is the correct explanation of (A)

b) (A) is true, but (R) is false

c) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

d) (A) is false, but (R) is true

Question : 3

Approximately, how many different chemical elements exist in the Earth?

a) 300

b) 200

c) 250

d) 100