Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

Which one of K, I, Cl and Li will display the highest first ionisation energy?
A. K
B. I
C. Cl
D. Li

seo-qna
Last updated date: 27th Mar 2024
Total views: 397.2k
Views today: 3.97k
MVSAT 2024
Answer
VerifiedVerified
397.2k+ views
Hint: It is an alkaline earth metal, it is a reactive metal that forms a dark oxide-nitride layer when exposed to air. It is the fifth most abundant element in Earth's crust and the third most abundant metal, after iron and aluminium.

Complete step by step answer:

Now, let us understand about ionization energy.
The ionization energy increases on moving from left to right along a period, because with increase in atomic number in a period, generally the effective nuclear charge increases due to which the electrons are tightly held. Similarly, on moving down the group due to which the shells become far from the nucleus, as the result nuclear attraction towards valence electrons decreases. This results in a decrease in ionization energy.

Let us understand why chlorine displays the highest first ionisation energy.
Cl needs only one electron to gain noble gas configuration while sulfur needs 2. Thus the nuclear charge of Cl is higher. The shielding effect in Cl is higher because there is one more electron in Cl than S. Valence electrons in Cl are pulled closer to the nucleus and tighter than that of S, requiring more energy to remove one electron from Cl than S. Hence, Cl has higher 1st ionization energy than that of S.

Note: Nuclear charge and shielding effect affects ionisation energy. The greater the number of protons, the stronger the nuclear charge. The greater the number of principal quantum shells, the greater the shielding (screening) effect of the valence electrons by the positively-charged nucleus.
Recently Updated Pages