13 Al 26.982

Aluminium

Post-transition metal · Group 13 · Period 3

Aluminium (symbol Al, atomic number 13) is the most abundant metal in the crust, lightweight and endlessly recyclable. It is classified as a post-transition metal and sits in group 13, period 3 of the periodic table.

Overview

Aluminium is the chemical element with atomic number 13 and the symbol Al. With a standard atomic weight of 26.982, it is a post-transition metal. In the periodic table it occupies group 13 and period 3, and under standard conditions it is normally a solid. Aluminium is the most abundant metal in the crust, lightweight and endlessly recyclable.

Atomic structure

An atom of Aluminium has 13 protons in its nucleus and, when neutral, 13 electrons arranged in the configuration [Ne] 3s2 3p1. Its standard atomic weight of 26.982 reflects the natural mix of its stable isotopes.

Discovery and place in the table

Aluminium was discovered in 1825 by Hans Christian Ørsted. It follows Magnesium (Mg) and precedes Silicon (Si) in order of atomic number.

Key properties of Aluminium
Atomic number 13
Symbol Al
Atomic mass 26.982
Category Post-transition metal
Group 13
Period 3
Electron configuration [Ne] 3s2 3p1
Phase at STP Solid
Discovered 1825 (Hans Christian Ørsted)