Apositively charged ion will bond with a) a negatively charged ion. b) a neutral atom. c) another positively charged ion. d) nothing else.

A positively charged ion will bond with A) a negatively charged ion.

Explanation:

An atom is neutral in nature. When electrons are removed from an atom, atom becomes positively charged or cation. and the atom gains electrons becomes negatively charged or anion. The cation bonds with the anion to maintain neutrality. The anion loses electrons to cation and thus an ionic bond is formed between the two.

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.