its freshly exposed shiny surface rapidly turns dull as a thin layer of sodium oxide forms: Other metals may oxidise more slowly. Gold and other very unreactive metals do not oxidise in air at all.

The shiny grey magnesium strip changes to a white powder called magnesium oxide. Learn more about making a reactivity series in this guide. For example, sodium is burned to make sodium oxide.

MoS 2 /graphene oxide (MoS 2 /GO) composites using a layer-by-layer method on SiO 2 templates as anodes for high-performance sodium-ion batteries. Image Credit: Juan Roballo/Shutterstock.com ...