Properties of metals, metalloids and nonmetals one or two properties very different from the expected norm, or that are otherwise notable. Sodium, potassium, rubidium, caesium, barium, platinum, gold Manganese Iron, cobalt, nickel, gadolinium, terbium, dysprosium, holmium, erbium, thulium Iridium Gold Mercury Lead Bismuth Uranium Plutonium Boron Boron, antimony Silicon Arsenic Antimony Hydrogen Helium Carbon Phosphorus Iodine Properties of metals, metalloids and nonmetals Metals appear lustrous (beneath any patina); form mixtures (alloys) when combined with other metals; tend to lose or share electrons when they react with other substances; and each forms at least one predominantly basic oxide. Most metals are silvery looking, high density, relatively soft
Nonmetal with the same tetragonal structure as tin; when decompressed—and depending on the speed of pressure release—metallic germanium forms a series of allotropes that are metastable at ambient condition. Germanium also forms a graphene analogue, germanene. Arsenic and antimony form several well known allotropes (yellow, grey, and black). Tellurium is known only in its crystalline and amorphous forms; astatine is not known to have any allotropes. Hydrogen and helium are estimated to make up approximately 99 per cent of all ordinary matter in the universe. Less than five per cent of the Universe is believed to be made of ordinary matter,