explain why an atom absorbs or emits energy in a very specific units?

Answer 1

The short answer is because energy is quantitized. In other words, energy occurs only in descrete packets, or "energy quanta."

Thank Max Planck for that answer. Read more about it here:

http://www.kutl.kyushu-u.ac.jp/seminar/MicroWorld1_E/Part3_E/P35_E/energy_quantum_E.htm

Answer 2

An atom has many different energy levels which are refered to as n-1 or n-2 ans so on. For each n an electron falls from, it gives off energy in the form of heat/light, it also gives off light when jumping up n. I think the most an atom can have is n-7 but it really depends on what kind of atom is it and what size is it (like how many energy orbitals does it have)

Answer 3

Hi. It takes a certain amount of energy to make an electron jump to a higher "orbit". This is also how much energy it gives off for the same basic reason.