Which unit is commonly used to measure density?

Density is commonly used in units of grams per cubic centimetre.

g/cm^3

Explanation:

Density=mass/volume = g/cm^3 and it is commonly expressed unit. But if you want, you can also convert it into kg/m^3 .

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.