Use the periodic table to answer the following questions:

(a) Identify an element with five electrons in the outer subshell.

(b) Identify an element that would tend to lose two electrons.

(c) Identify an element that would tend to gain two electrons.

(d) Identify the group having metal, non-metal, liquid as well as gas at the room temperature. 

 (a) The general electronic configuration of the elements having five electrons in the outermost subshell is ns²np³. This electronic configuration is characteristic of elements of group 15. Hence element belongs to nitrogen family (group 15).
(b) The elements which have a tendency to lose two electrons must have two electrons in the valence shell. Therefore their general electronic configuration should be ns². This electronic configuration is characteristic of elements of group 2. Hence element belongs to alkaline earth family (Group 2).
(c) The elements which have a tendency to gain two electrons must have six electrons in the valence shell. Therefore their general electronic configuration is ns²np⁴. This electronic configuration is characteristic of group 16 elements. Hence element belongs to oxygen family (Group 16).
(d) A metal which is liquid at room temperature is mercury and belongs to group 12. A non-metal which is gas at room temperature is nitrogen (Group 15), oxygen (Group 16), flourine and chlorine (Group 17) and inert gases (Group 18). A non-metal which is liquid at room temperature is bromine (Group 17).