Question

Assertion: When an atom in group $1\,A$ of the periodic table undergoes radioactive decay by emitting a positron, the resulting element belongs to zero group.
Reason: When an atom emits a positron, its atomic number increases by one unit.

• A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion
• B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
• C. Assertion is true but Reason is false
• D. Assertion is false but Reason is true

Answer 1

Answer: (C)

Positron emission :
$^{b}_{c}X \rightarrow ^{b}_{a-1}X +^{0}_{1}\beta$
positron
Therefore, after positron emission, atomic number of the atom decreases by one and mass number remains unaffected.