If Z = 3, what would be the valency of the element? Also, name the element

Explanation

The symbol Z stands for the atomic number of an element. By saying that Z = 3, we mean that the atomic number of this element is 3. The electronic configuration of the element having atomic number 3 is `underset("2, 1")("K L")`. It has 1 electron in its outermost shell (L shell). So, one atom of this element can lose 1 electron to achieve the nearest inert gas electron arrangement of `underset(2)(K)` (which is the same as that of helium gas). Since one atom of this element loses 1 electron to achieve the inert gas electron configuration, thereforem its valency is 1. The element having atomic number 3 is lithium.