Question

Which element will form a cation in a salt?

• A. Sodium
• B. Fluorine
• C. Oxygen
• D. Carbon

Answer 1

The correct option is A

Sodium

Let's write the electronic configuration for these elements.

Sodium - 2, 8, 1

Fluorine - 2, 7

Oxygen - 2, 6

Carbon - 2, 4

In order to obtain a stable octet configuration,
(i) Sodium needs to donate one electron.
(ii) Fluorine needs one electron.
(iii) Oxygen needs two electrons
(iv) Carbon needs to share four electrons.

Therefore sodium will form a cation in a salt as it is the only element in the given options which donates its electron naturally.