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
Metalloid Silicon is present in silatrane, a highly toxic rodenticide. Long-term inhalation of silica dust causes silicosis, a fatal disease of the lungs. Silicon is an essential trace element. Silicone gel can be applied to badly burned patients to reduce scarring. Salts of germanium are potentially harmful to humans and animals if ingested on a prolonged basis. There is interest in the pharmacological actions of germanium compounds but no licensed medicine as yet. Arsenic is notoriously poisonous and may also be an essential element in ultratrace amounts. During World War I, both sides used "arsenic-based sneezing and vomiting agents…to force enemy