I got the other ones but I can't figure thins out. I asked my uncle but he doesn't know either. Please help!

Sodium has an atomic number of 11 and has a net charge of 0. When sodium combines with chlorine, it has a net charge of +1. Why?
A) Sodium loses a negative electron when forming chemical bonds.
B) Sodium gains a + proton when forming chemical bonds.
C) Sodium loses a + proton when forming chemical bonds.
D) Sodium shares a negative electron with chlorine.

Two horses begin at rest. after a few seconds, horse a is traveling with a velocity of 10 m/s west, while horse b is traveling with a velocity of 13 m/s west. which horse had a greater acceleration? a. horse a because its change in velocity was greater than horse b's in the same time. b. horse b because its change in velocity was greater than horse a's in the same time. c. horse b because its change in velocity was the same as horse a's, but it took less time. d. both horses had the same acceleration.