Life vest floats in the water therefore what do you know about the life vests density?

their density is only lighter than water because of the air inside. without the air you would sink even if you were holding it firmly.

Explanation:

each chemical family is represented as a group or column on the periodic table. based on chemical properties, there are 6 types of chemical families. group 1 represents alkali metals, group 2 represents alkaline earth metals, groups 3 to 12 represent transition metals, groups 13 to 16 represent non-metals and other metals, group 17 represents halogens and group 18 represents noble gases.