I was wondering why and how there is a 'hydrogen spectrum'.. since hydrogen has only 1 electron, so shouldn't it give off/have only 1 colour or frequency not multiple...

it has one electron, but there are many energy levels.

 

a single atom will give off only 1 colour at any one time, but when you have a few you'll get a spectrum.

ok, but why are there multiple energy levels for the hydrogen atom when there is only 1 electron ?

It is a result of quantum mechanics.

 

the wave function can exist in several energy states that do not have the energy to remove the electron from the atom.

 

think of it like a satellite orbiting a planet, that satellite even if it is the only one, can orbit at many different altitudes. well, same for electrons although the altitudes it can orbit at are quite limited so its not a perfect analogy.

ok sweet, thanks.