Question

Aufbau and Periodic Trends
For eachof the elements or ions given below
He, Ti^2+, H+ write
The four quantum numbers or the lowest energy electron
The four quantum numbers of the highest energy electron

Answer 1

He Atomic No. 2

Electronic Configration = IS².

Thus, in he both electrons are in same orbital & only one orbital is occupied, i.e. , s. orbital of list shell. So, the electrons can be compared as lowest as well as highest energy electrons themselves.

3d e^-s are highest energy e^-s & is electrons are lowest energy e^-s.

Note : ( i ) In T_i 3d orbital will be filled after us orbital but it will loose e^-s from 4s before 3d.

( ii ) Paring in A - orbitals will not take place until each orbital gets 1 e^- , that is why m_e for d orbital e^-s is written seperately altough they have same energy degenerate