Answer:
The cation is smaller.
Explanation:
Electronic configuration of Lithium atom is as follow,
Li = 1s², 2s¹
while, Electronic configuration of Lithium cation is as follow,
Li⁺ = 1s²
The Lithium Cation is smaller because,
i) Less Energy Levels:
As depicted in electronic configurations, the valence shell of Li atom is 2 while, that of Li cation is 1 as a result the distance of valence electrons and nucleus has decreased resulting in small size.
ii) Less Shielding Effect:
The effect in which the core electrons shield the valence electron from nucleus pull is known as shielding effect. In Li cation there are no core electrons hence, the electrons are more attracted towards proton resulting in small size.
iii) More Nuclear Charge:
In Li atom there are three protons and three electrons so, three protons attract three electrons and the game run some what balance. But, as tone electron is lost in Li Cation, the proton side gets stronger and apply more pull on electrons and made them more closer to the nucleus resulting in size decrease.
