Electronic Configuration

Blocks

The periodic table is split into four main blocks depending on electronic configuration. S block, p black, d block and f block

Sub shells

Increase in energy from s,p,d,f. The only exception is that 3d has a slightly higher energy than the 4s orbital

What does electronic configuration represent

The number of electrons in each shell, sub shell and orbital of an atom

1s1

The big one represents the shell number, “s” represents subshell and the small one represents the number of electrons

Principal energy level one

Subshell - 1s and maximum number of electrons is 2

Principal energy level two

Subshells - 2s,2p. Maximum number of electrons is 8

Principal energy level three

Subshells - 3s,3p,3d. Maximum number of electrons is 18

Principal energy level four

Subshells - 4s,4p,4d,4f. Maximum number of electrons is 32

Ions

The transition metals fill the 4s sub shell before the 3d sub shell but lose electrons from the 4s first and not the 3D, the 4s sub shell is lower in energy

Helium [He]

1s2 - the first 2 electrons

Neon [Ne]

1s2, 2s2, 2p6 - first 10 electrons

Argon [Ar]

1s2, 2s2, 2p6, 3s2, 3p6 - first 18 electrons