3 Types of Electron Configuration

Silicon (Si) – 1s2 2s2 2p6 3s2 3p2

The first number dictates the energy level. The level stands for the sub-level, and the second number shows how many electrons are in that sub-level.

Orbital Box
Notation

Longhand
Notation

The number and letter under the box show the energy level number, then the sub-level. The arrows represent an electron and it's spin.

Noble-Gas
Notation

Potassium
[Ar] 4s1

This configuration takes the element just before the one you want and allows you to just add the missing electrons. This way assumes you know the longhand of the smaller element.