Question

Description of Moeller Chart (Filling order of atomic orbitals) in a para

Answer 1

We  write the  atomic orbitals in the principal quantum number, by rows.

1s
2s   2p
3s   3p   3d
4s   4p   4d   4f
5s   5p  5d    5f   5g ...
6s   6p   6d    6f   ....
7s  7p  ..
8s


This is called Moeller's Rubric.  Now draw arrows in South West direction (to bottom left from top right diagonally).   That indicates the order of filling of electrons in atomic orbitals.  This agrees with the grouping of elements (according to outermost orbitals).  The order of filling of electrons and the order of orbitals are in agreement with Auf-bau principle.

Answer 2

That indicates the order of filling of electrons in atomic orbitals.  This agrees with the grouping of elements (according to outermost orbitals).  The order of filling of electrons and the order of orbitals are in agreement with Auf-bau principle.