( use ↑ and ↓ please)
Sodium Na
$4Na$ $+$ $O_2$ $\longrightarrow$ $2Na_2O$ Sodium and oxygen give sodium oxide $Na_2O$ $+$ $H_2O$ $\longrightarrow$ $2NaOH$ Sodium oxide and water give sodium hydroxide
Magnesium Mg
$2Mg$ $+$ $O_2$ $\longrightarrow$ $2MgO$ Magnesium and oxygen give magnesium oxide $MgO$ $+$ $H_2O$ $\longrightarrow$ $Mg(OH)_2$ Magnesium oxide and water give magnesium hydroxide
Iron Fe
$3Fe$ $+$ $2O_2$ $\longrightarrow$ $Fe_3O_4$ Iron and oxygen give iron(II,III)oxide