A lithium atom has positively charged protons and negatively charged electrons. The sum of the charges represents the charge of the lithium atom. Find the charge of the atom

At its neutral state, an element has equal number of protons and electrons. If not, they occur as ions. The most stable elements are the noble gases. The nearest noble gas to Lithium is Neon, which is one proton lower than Lithium. Hence, when Lithium has a charge, it is naturally + 1 because it has to give one electron to be as stable as Neon.