Which element has :
(a) two shells, both of which are completely filled with electrons ?

(b) the electronic configuration 2,8,2 ?

(c) a total of three shells, with four electrons in its valence shell ?

(d) a total of two shells, with three electrons in its valence shell ?

(e) twice as many electrons in its second shell as its first shell ?

Question

Which element has :
(a) two shells, both of which are completely filled with electrons ?

(b) the electronic configuration 2,8,2 ?

(c) a total of three shells, with four electrons in its valence shell ?

(d) a total of two shells, with three electrons in its valence shell ?

(e) twice as many electrons in its second shell as its first shell ?

Philoid · Accepted Answer

(a) So in this electronic configuration there are three shells and there are 2 electrons in its last shell, so the total electrons are 12. So this element is Alluminium.

(b) The element which has two shells and both are completely filled with electrons is Neon. Neon has 2 electrons in its first shell and 8 electrons in the second.

(c) The element which has three shells and 4 electrons in its valence shell is Silicon.

(d) The element which has two shells and two electrons in its valence shell is Boron (2,3).

(e) As we know only 2 electrons can exist in the first shell, so it means there are 4 electrons in the valence shell of this element. Therefore this element is Carbon (2,4).