Question

*Which of the given element has valancy 2? (numbers shown in bracket represent atomic number)*

1️⃣ C(4)
2️⃣ O(8)
3️⃣ N(7)
4️⃣ Cl(17)​

Answer 1

Answer:

0(8)

Explanation:

The valency of oxygen is 2, because it needs two atoms of hydrogen to form water.

Answer 2

Required Answer:-

Valency 2 means +2 or -2, there can be gain/loss of 2 electrons from the outermost shell in the atom. Valency also helps us to determine the no. of Valence electrons in the outermost shell$.$

The atom can gain/loss electrons to obtain an octet configuration. This we can decide by the electronic configuration:

1. C(6): 2,4
2. O(8): 2,6
3. N(7): 2,5
4. Cl(17): 2,8,7

Clearly, Oxygen (O) needs two electrons for completing the octet configuration of Neon. Hence, Option 2) O is the correct option.