What are two reasons scientists might use a model to study what happens on the atomic level when something explodes?
A. The process cannot be understood without a model.
B. The molecules in the reaction are too small to see.
O C. Explosions occur too slowly to study easily.
D. The process is very dangerous to study.

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.