Answer:
Neon (Ne)
Hydrogen (H)
Argon (Ar)
Iron (Fe)
Calcium (Ca)
Deuterium, an isotope of hydrogen that has one proton and one neutron.
Plutonium (Pu)
F-, a fluorine anion.
Explanation:
I got u
Hundreds of them....hope it helps
This should help you with your question:
Gravitational pull = 9.8 m/s^2
1/2 x 9.8 x 7^2 = 240.1 m
The rock has fallen 240.1 m.
I cannot help you with the rest, but this should give you a headstart.