Answer :
(a) The charge and full ground-state electron configuration of the monatomic ion is, (+1) and 
(b) The charge and full ground-state electron configuration of the monatomic ion is, (-3) and 
(c) The charge and full ground-state electron configuration of the monatomic ion is, (-1) and
Explanation :
For the neutral atom, the number of protons and electrons are equal. But, they are unequal when the atoms present in the form of ions or the atom has some charges.
When an unequal number of electrons and protons then it leads to the formation of ionic species.
Ion : An ion is formed when an atom looses or gains electron.
When an atom looses electrons, it will form a positive ion known as cation.
When an atom gains electrons, it will form a negative ion known as anion.
(a) The given element is, Rb (Rubidium)
As we know that the rubidium element belongs to group 1 and the atomic number is, 37
The ground-state electron configuration of Rb is:
This element will easily loose 1 electron and form 
ion which attain stable noble gas electronic configuration.
The full ground-state electron configuration of Rb ion is:
(b) The given element is, N (Nitrogen)
As we know that the nitrogen element belongs to group 15 and the atomic number is, 7
The ground-state electron configuration of N is:
This element will easily gain 3 electrons and form 
ion which attain stable noble gas electronic configuration.
The full ground-state electron configuration of N ion is:
(c) The given element is, Br (Bromine)
As we know that the bromine element belongs to group 17 and the atomic number is, 35
The ground-state electron configuration of Rb is:
This element will easily gain 1 electron and form 
ion which attain stable noble gas electronic configuration.
The full ground-state electron configuration of Br ion is:
