bohrs theory

• electrons revolve around nucleus in orbital or shell
• electrons have a definite amount of energy when in a shell this is why the are called energy levels/ energy depends on the distance from the nucleus
• energy levels are called principal quantum number
• ground state 


  electrons occupy lowest energy level
• when electron is exited it jumps to higher energy level/ exited state is unstable and temporary
• when electron falls back to ground state energy is lost a photon is emitted / light or radiation
• only fixed amounts of light can be given off as electrons can only fall back to certain definite energy levels/ definite frequency wavelength and appears as a colour
• further apart energy level the greater the energy given out / higher frequency and wavelength of light is shorter