(a) how many neutrons are present in c-14 isotope of carbon?
(b) how many protons does `He^(2+)` ion posses?
(c ) How many electons can be filled in the third orbit of an atom at the maximum ?

Explanation

(a) C-14 isotope of carbon has mass number 14 and atomic number 6. In this isotope,
No of protons = Atomic no =6
No of electrons = Atomic no =6
No of electrons = Mass no - Atomic no
=14-6=8.
(b) `He^(2+)`ion (z=2) has two protons.(c ) The third orbit of an atom can have maximum of 8 electrons