The particles are represented by a name and by a symbol. The symbols have three important numbers. The subscripted number is the atomic number. The atomic number represents the number of protons. The superscripted number located to the left of the element symbol is the mass number. The mass number represents the number of protons plus neutrons. Thus, simple subtraction of these two numbers provides the number of neutrons. 

In each row, the name refers to the particles as an ion. This means that the particle has an overall charge; it is not zero.  All the elements in this table are main group elements or representative elements. For such elements, the charge of the ions are predictable. It is predictable based upon the location of the element in the Periodic Table. For instance, elements in the alkali metal family (Group 1) all form 1+ ions. Elements in the alkaline earth metal family (Group 2) all form 2+ ions.  And as a final example, elements in the halogen family (Group 17) all form 1- ions. The color-coded graphic below will help you relate the location of elements in the Periodic Table with the ion charge.
 

Charge is the result of protons and electrons - the two charged subatomic particles. Protons and electrons have the opposite type of charge. So if a particle is charged it must have unequal numbers of protons and electrons. A positively-charged ion will have more protons than electrons. A negatively-charged ion will have less electrons than protons. Pause and re-read those two statements and digest the idea. The number of protons is determined by the atomic number. So to determine the number of electrons, you will have to subtract the charge from the number of protons. Of course this means that you would be subtracting a negative number for any negatively-charged ion.

The graphic below summarizes these ideas.