what sentence describes all atoms of one element A. They have the same number of isotopes B. They have the same properties C. They have the same number of protons D. They have the same number of neutrons

C. They have the same number of protons.

Explanation:

Even though in isotopes, there's uneven number of neutrons, there's always same number of protons.

Hope it helps.

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.