Convection currents are driven by differences in? •Mass
•Volume
•Density
•Weight

Density

Explanation:

The density, of a substance is its mass per unit volume. The symbol most often used for density is ρ, although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume: {\displaystyle \rho ={\frac {m}{V}}} where ρ is the density, m is the mass, and V is the volume

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.

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.