What volume of hydorgen (L) is produced from the complete reaction of 54.49 g of magnesium metal of STP? Mg(s) + 2HCl(aq) -> MgCl2(aq) + H2(g)

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom

Ido not understand.