Aluminum (Al)

Aluminum properties

Atomic number

13

Atomic mass

26.982 u

Category

Post-transition metal

Group

13

Period

3

Block

p-block

State at room temp.

Solid

Electronegativity

1.61

Melting point

933.47 K (660.3 °C)

Boiling point

2,743 K (2,469.8 °C)

Density

2.7 g/cm³

Valence electrons

3

Common charges

+3

Oxidation states

+3

Atomic radius

184 pm

Ionization energy

5.986 eV

Electron affinity

0.441 eV

Radioactive

No, has stable isotopes

Discovered

1825

Aluminum electron configuration

The electron configuration of Aluminum (Al) is [Ne] 3s2 3p1. Its 13 electrons are arranged in shells as 2, 8, 3.

Protons, neutrons and electrons in Aluminum

A neutral Aluminum atom has 13 protons and 13 electrons. Most Aluminum atoms have about 14 neutrons: the atomic mass rounded to 27, minus the atomic number 13.

Neutrons are approximate: atoms of the same element can have different numbers of neutrons (isotopes). Atomic number and mass

How many valence electrons does Aluminum have?

3

Aluminum has 3 valence electrons in its outermost shell, shell 3. These are the electrons involved in chemical bonding.

See every element: Periodic table with valence electrons

Aluminum orbital diagram

Each box is an orbital that holds up to two electrons with opposite spins (↑↓). The inner shells are the same as the noble gas in brackets. How to write electron configurations

Molar mass of Aluminum

26.982 g/mol

One mole of Aluminum atoms (6.022 × 10²³ atoms) has a mass of 26.982 grams. Use this value to convert between grams and moles.

Compounds containing Aluminum

Aluminum facts

• Aluminum is the most abundant metal in Earth's crust, but it is never found in nature as a pure metal.
• When the Washington Monument was completed in 1884, it was topped with a small pyramid of aluminum, then a rare and costly metal.
• Aluminum (Al) has atomic number 13 and is a solid at room temperature. It was discovered in 1825.

Position in the periodic table

Aluminum is element 13, in period 3 and group 13 of the periodic table, in the p-block.

All post-transition metals

Uses of Aluminum

Aluminum is used wherever a light, corrosion-resistant metal is needed: drink cans, foil, window frames and the bodies and frames of aircraft, cars and trains. Because it conducts electricity well for its weight, aluminum is the standard metal for overhead high-voltage power lines. It is also used in cookware and in heat sinks for electronics, and aluminum sulfate helps purify drinking water.

Who discovered Aluminum?

Danish physicist Hans Christian Ørsted produced the first impure aluminum in 1825 in Copenhagen, by reacting aluminum chloride with potassium amalgam. Friedrich Wöhler improved the method in 1827 and made purer metal.

Where does the name come from?

Aluminum comes from alum, from the Latin alumen, a name for salts used since ancient times to fix dyes. Humphry Davy proposed alumium and then aluminum; the spelling aluminium later became standard in Britain and much of the world.

Discovery timeline