Answer:
Step-by-step explanation:
Mass number = No of neutrons + no of protons 
Let no of protons be p , No of neutrons = p + 12 
Putting the given values 
88 = p + 12 + p 
76 = 2p 
p = 38 
n = 50 
a ) Atom is Strontium ( Sr ) 
Electronic configuration 
1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶5s²
b ) Sr²⁺ 
1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶