Asubstance is composed of only one kind of atom and can't be separated into simpler substances or converted into another substance by chemical processes. under which category would you classify this substance?

a.) element
b.) compound
c.) solution
d.) suspension

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

< > according to newton's third law of motion, forces always act in equal but opposite pairs. another way of saying this is for every action, there is an equal but opposite reaction.< >