Question

In which of the following pairs, the second element is larger than the first?

• A. Nitrogen and phosphorus
• B. Bromine and chlorine
• C. Barium and strontium
• D. Magnesium and beryllium

Answer 1

The correct option is A Nitrogen and phosphorus

Atomic radius of an atom is defined as the distance between the center of its nucleus and its outermost shell. Down the group, the atomic radius increases due to addition of shells. Therefore, phosphorus is larger than nitrogen as phosphorus comes after nitrogen in the 15th group.

For other options the bromine, barium and magnesium are larger than chlorine, strontium and beryllium respectively because bromine, barium and magnesium are lying below chlorine, strontium and beryllium in the same group.