The change of an atom from the excited state to the ground state always requires

emission of electromagnetic radiation

Explanation:

When an atom is in its ground state, its electrons fill the lower energy orbitals completely before they begin to occupy higher energy orbitals.  

On the other hand, when an atom is excited (it has left its ground state, in which each electron occupies its place in its orbit, around the nucleus),  some electron jumps out of the orbit it occupied in its fundamental state to an outer orbit, further away from the nucleus and then return to the ground state, emitting in the form of electromagnetic radiation (light which may be visible or not) the energy received.  

So, when an excited electron passes from an outer orbit to the ground state, it produces electromagnetic radiation of a specific wavelength that depends on the amount of energy the electron releases in the process.

Therefore:

the closer the planet is to the sun, the larger the gravity

false.

explanation:

this statement is false. after falling for 5 seconds, its speed will not be 100 m/s.