Question

Which of the following is the most electropositive element?
A) Lithium
B) Boron
C) Carbon
D) Nitrogen

Answer 1

Hint: Electropositive character is a tendency of an element to lose its electrons. The electropositive character of elements decreases as we move from the left to right in the periodic table (across the period) and increases as we move from top to bottom (down the group).

Complete Solution :
- Electropositivity or electropositive character of an atom is a tendency to lose or donate its electron to form a positively charged ion i.e. cation. This property is shown by the metallic elements like alkali or alkaline earth metal.
- The electropositive character of elements decreases as we move from the left to right in the periodic table (across the period) and increases as we move from top to bottom (down the group).
In the periodic table, the alkali and alkaline earth metal can easily donate their valence shell electrons to attain the nearest noble gas configuration.
- Lithium is an alkali earth metal. Its electronic configuration is as shown below,
$\text{ Li = 1}{{\text{s}}^{\text{2}}}\text{ 2}{{\text{s}}^{\text{1 }}}$
- Lithium loses its one $\text{ 2s }$ electrons to attain the noble gas configuration of helium. It donates its electron to form a $\text{ L}{{\text{i}}^{\text{+ }}}$ cation.
- The lithium is situated at the left end of the periodic table. It is more electropositive than the other elements as it has the largest size. Due to its bigger size the valence electron experiences less nuclear charge effect and easily donate its electrons.
Here, the increasing order of electropositive character is as shown below:
$\text{ N }<\text{ C }<\text{ B }<\text{ Li }$

So, the correct answer is “Option A”.

Note: Note that, the electropositive character is oppositely related to the electronegativity. Elements tend to gain electrons. Therefore, highly electropositive elements have very low electronegativity and vice versa.