Question

write the electronic configuration of the following elements calculate it's valenc electrons and valency

(A) flourine. (B) neo
n. (C) oxygen. (D) magnesium.​

Answer 1

Answer:-

A) Flourine (F)

Atomic number (Z) = 9

That means,

Number of electrons/protons = 9

Electronic Configuration: 1s² 2s² 2p⁵

Valence electrons are nothing but number of electrons in the outermost shell.

Hence, Valence electrons of F = 2 + 5 = 7

Valency is the combining capacity of an element.

If the number of valence electrons are greater than 4 , then the valency of the element = 8 - Valence electrons.

Hence, Valency of Flourine = 8 - 7 = 1.

B) Neon (Ne)

Atomic number = 10

Configuration : 1s² 2s² 2p⁶

Valence electrons = 2 + 6 = 8

Valency = 8 - 8 = 0

C) Oxygen (O)

Atomic number = 8

Configuration : 1s² 2s² 2p⁴

Valence electrons = 2 + 4 = 6

Valency = 8 - 6 = 2

D) Magnesium (Mg)

Atomic number = 12

Configuration : 1s² 2s² 2p⁶ 3s²

Valence electrons = 2

Valency = 2 because valence electrons of Mg are less than 4.