Answer: Objects with like charge repel each other.
Answer:
It only needs one electron.
Because some machine might not work and would give you the wrong answer
Volume=Mass over density. V= 220/55. V=4cm^3
Answer:

Explanation:
R = Rydberg constant = 
= Principal quantum number of an energy level = 2
= Principal quantum number of an energy level for the atomic electron transition = 4
Wavelength is given by the Rydberg formula

The wavelength of the light emitted is
.