Question

Among the elements with atomic numbers 9, 12, 16 and 36 which is highly electropositive?
a.) Element with atomic number 9
b.) Element with atomic number 12
c.) Element with atomic number 16
d.) Element with atomic number 36

Answer 1

Electro positivity is the property of elements that decreases in elements as we move across the group and increases in the elements as we move down the group.

Complete step by step answer:
Electro positivity is the tendency of an element to lose its electron to attain the nearest stable inert gas configuration. In the periodic table as we across the period electropositivity decreases as the effective nuclear charges of the elements increases while we move down the group though electropositivity increases as nuclear charge increases but it is counterbalanced by increase in number of shells so overall there is no increase in electropositivity. Electropositivity is measured by writing the electronic configuration of elements and seeing how many electrons are present in the last subshell.
Elements which have electrons less than 3 in their last subshell are highly electropositive than elements which have 4 or more than 4 electrons in their last subshell.
Therefore, as we increase the number of electrons in the last subshell electropositivity decreases.
As per option A, Electronic configuration of an element with atomic number 9 comes out $1{{s}^{2}}2{{s}^{2}}2{{p}^{5}}^{{}}$

As per option B, Electronic configuration of an element with atomic number 12 comes out $~1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}^{{}}$

As per option C, Electronic configuration of an element with atomic number 16 comes out $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{4}}^{{}}$

As per option D, Electronic configuration of an element with atomic number 16 comes out $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{10}}4{{s}^{2}}4{{p}^{6}}$

From all the above options, option B that is an element with atomic number 12 is highly electropositive compared to others as it has only two electrons in the last shell.
So, the correct answer is “Option B”.

Note: Electropositivity is the tendency of an element to lose its electron to attain the nearest stage inert gas configuration. In the periodic table as we across the period electropositivity increases while we move down the group electropositivity increases.