Aufbau principle:
Electrons are added one at a time from the lowest energy orbitals available until all the orbitals are filled.
According to the Aufbau principle, electrons fill lower energy orbitals first.
(i) Boron (Z = 5)
Electronic configuration =
(ii) Neon (Z = 10)
Electronic configuration =
(iii) Aluminium (Z = 13)
Electronic configuration =
(iv) Chlorine (Z = 17)
Electronic configuration =
(v) Calcium (Z = 20)
Electronic configuration =
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