Question

In modern periodic table nitrogen is placed just before oxygen in the 2nd period because:

• A. Nitrogen has bigger atomic radius than oxygen.
• B. Oxygen is more electronegative than nitrogen.
• C. Oxygen has one more proton in its nucleus than nitrogen.
• D. The given statement is false. In the modern periodic table oxygen is placed before nitrogen.

Answer 1

The correct option is C

Oxygen has one more proton in its nucleus than nitrogen.

Elements are classified based on on their increasing atomic number in the modern periodic table. So all the other reasons (even correct) will not be considered while deciding the placement of elements in the periodic table.

Atomic number is the number of protons present in the nucleus of an atom. Nitrogen has 7 protons and oxygen has 8. Hence nitrogen is placed just before oxygen.