When lithium metal reacts with fluorine gas it forms the ionic compound lithium fluoride (LiF). What is the correct electron configurations of the ions formed

The electronic configuration of ions formed are:

Li+ (2) => 1s2

Cl- (18) => 1s2 2s2 2p6 3s2 3p6

Explanation:

Lithium metal, Li will lose 1 electron to lithium ion Li+. Chlorine atom, Cl will receive the 1 electron to form the chloride ion Cl- as shown by the following equation below:

Li —> Li+ + e

Cl+ e —> Cl-

Combine both equation

Li + Cl + e —> Li+ + Cl- + e

Cancel out 'e'

Li + Cl —> Li+ Cl-

Thus, we can write the electronic configuration for the reaction as follow:

Before reaction:

Li (3) => 1s2 2s1

Cl (17) => 1s2 2s2 2p6 3s2 3p5

After reaction

Li+ (2) => 1s2

Cl- (18) => 1s2 2s2 2p6 3s2 3p6

Therefore, the electronic configuration of the ions formed are:

Li+ (2) => 1s2

Cl- (18) => 1s2 2s2 2p6 3s2 3p6