Light metal
{{Short description|Metals with low densities}}
{{periodic table (micro) | title = Light metals
| caption = Metals and metalloids
with a density < 5 g/cm3
| mark = Li,Be,B,Na,Mg,Al,Si,K,Ca,Sc,Ti,Rb,Sr,Y,Cs,Ba,Fr
}}
{{sidebar periodic table}}
A light metal is any metal of relatively low density.Jackson JA, Mehl JP, Neuendorf KKE (eds) 2005, Glossary of Geology, 5th ed., American Geological Institute, Alexandria, {{ISBN|0-922152-76-4}}, p. 371 These may be pure elements, but more commonly are metallic alloys. Lithium and then potassium are the two lightest metallic elements.
Magnesium, aluminium and titanium alloys are light metals of significant commercial importance.Brandes EA & Brook GB (eds) 1998, Light Metals Handbook, Butterworth Heinemann, Oxford, {{ISBN|0-7506-3625-4}}, p. viii Their densities of 1.7, 2.7 and 4.5 g/cm3 range from 19 to 56% of the densities of other structural metals,Polmear I 2006, Light Alloys: From Traditional Alloys to Nanocrystals, 4th ed., Butterworth Heinemann, Oxford, {{ISBN|0-7506-6371-5}}, p. 1 such as iron (7.9) and copper (8.9).