
Period 4 elements
Period 4 is the first row where transition metals appear. It runs from potassium to krypton and includes iron, copper, zinc and nickel - the metals that power everything from kitchen knives to electric grids.

Period 4 is the first row where transition metals appear. It runs from potassium to krypton and includes iron, copper, zinc and nickel - the metals that power everything from kitchen knives to electric grids.