 Monatomic ions consist of a single atom with a positive or negative charge resulting from the loss or gain of one or more valence electrons.

 Cations are positively charged ions.  When the metals in Groups 1A, 2A, 3A lose electrons, they form cations with positive charges equal to their group  For Example: Potassium (K) is in group 1A, having a 1+ charge when forming into a cation Magnesium (Mg) is in group 2A, having a 2+ charge when forming into a cation Aluminium (Al) is in group 3A, having a 3+ charge when forming into a cation

 Anions are negatively charged ions.  Nonmetals tend to gain electrons to form anions, so the charge of a nonmetallic ion is negative.  The charge of any ion of a Group A nonmetal (5A, 6A, 7A) is determined by subtracting 8 from the group number.

 For example:  Fluorine is in Group 7A that forms a 1- charge (7- 8= -1)  Sulfur is in Group 6A that forms a 2- charge (6- 8 = -2)  Nitrogen is in Group 5A that forms a 3- charge (5-8=-3)  When these elements form into anions, there names change. The stem of the element name stays and the end changes to –ide.

 Many of the transition metals (Group 1B-8B) form more than one cation with different ionic charges and some have only one.  The charges of the cations of many transition metal ions must be determines from the number of electrons lost.  For example:  Iron (transition metal) forms two types of cations- (two electrons lost) which is named iron(II) and is read *iron two ion* & (three electrons lost) which is named iron(III) and is read *iron three ion*  Silver another transition metal only has one ionic charge, so its name as a cation wont have a Roman numeral it would just be  The Roman numeral represents the amount of charge on the ion.

 Polyatomic ions are composed of more than one atom.  The names of most polyatomic anions end in –ite or –ate.  They can either be cation or anion