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 electronic configuration of an element having 5 electrons in its outermost subshell should be $n s^{2} n p^{5}$. This is the electronic configuration of the halogen group. Thus, the element can be $F$, CL, Br, I, or At.
(b) An element having two valence electrons will lose two electrons easily to attain the stable noble gas configuration. The general electronic configuration of such an element will be ns2. This is the electronic configuration of group 2 elements. The elements present in group 2 are Be, Mg, Ca, Sr, Ba.
(c) An element is likely to gain two electrons if it needs only two electrons to attain the stable noble gas configuration. Thus, the general electronic configuration of such an element should be ns2 np4. This is the electronic configuration of the oxygen family.
(d) Group 17 has metal, non–metal, liquid as well as gas at room temperature.