7. Which object is excellent at holding onto electrons?

Insulator

Explanation:

d.) circle motion requires a force to give it a centripetal acceleration.

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.