What is the sum of 2 + 0.42 + O 4 ones, 2 tenths, 2 hundred
O 4 ones, 2 tens, 2 hundreds
O 2 ones and 6 tenths

9.082

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.