How are simple cations and anions named ?

Explanation:

The cations are positively charged ions and the anions are negatively charged ions.

Simple cations and anions are named:

Cations that are formed from metal atoms have the same name as metal.  If a metal can form cations of different charges, the positive charge is indicated by a Roman number in parentheses after the name of the metal. Cations formed from non-metal atoms have names that end in -ium.

The names of monoatomic anions, as well as some polyatomic anions that do not contain oxygen, are formed by replacing the termination of the element's name with –ide.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.