Question

Which element from the following has highest ionisation energy?

(a) P, Na, Cl
(b) F, O, Ne
(c) Ne, He, Ar

Explain your choice. ​

Answer 1

Answer:

a) Cl

b)Ne

c)He

Explanation:

What is Ionisation Energy?

The minimum amount of energy required to remove an electron from the valence shell of an isolated neutral gas atom.

• It is represented by I.E.

Variation of Ionisation Energy in a period :

Generally ionisation energy increase as we move from left to right side along a period, because with increase in atomic number in a period, nuclear charge increases and hence electrons are more tightly held.

Variation of Ionisation Energy in a group:-

On moving downwards the group valence shell become far away from the nucleus and thus nuclear attraction towards valence electrons decreases which results decreasing in Ionisation Energy.

Important Point :-

Nitrogen has half filled 'p' orbital. So it requires more ionisation energy to remove an electron.

Explanation:-

a) P , Na , Cl

Atomic number of :-

P - 15

Na - 11

Cl - 17

Hence, these three belongs to same period. i.e third period. As above mentioned Ionisation Energy increases with increase in atomic number in a period. So highest atomic number element is Cl(17). So more Cl have more Ionisation Energy.

b) F, O, Ne

Atomic number of :-

F - 9

O - 8

Ne - 10

Hence these three elements belongs to second period.As above mentioned Ionisation Energy increases with increase in atomic number in a period.So highest atomic number element is Ne(10). So Ne have more Ionisation Energy.

c) Ne , He , Ar

Atomic number of :-

Ne - 10

He - 2

Ar - 18

As these three are belongs to noble gaeses and VIIA group elements.As above mentioned Ionisation Energy decreased in group as we are moving down. Hence we need to choose lowest Atomic number element. i.e He(2). Hence , He requires more Ionisation Energy.

Answer 2

★ Answer : (C.) Ne,He,Ar

★Explaination :

Metals have low ionisation energy and non-metals have high ionisation energy. Also, across the period, ionisation energy tends to increase. The elements P, Na and Cl belong to the third period. Na - Group 1, P - Group 15 and Cl - Group 17.

★What is Ionization

→Ionization, in chemistry and physics, any process by which electrically neutral atoms or molecules are converted to electrically charged atoms or molecules (ions). Ionization is one of the principal ways that radiation, such as charged particles and X rays, transfers its energy to matter.

★Hope it will help you★