Question

two elements having same number of protons and electrons but different number of neutrons

Answer 1

Elements have the same number of protons and electrons but different number of neutrons. But some elements like helium, carbon, nitrogen, oxygen, magnesium, calcium, silicon, sulphur have all the three as the same number.
Some elements which have same electrons and protons are:
Hydrogen H
Sodium Na
Aluminum Al
Chlorine Cl
Potassium K.
Hope it helps you.