1. Electromagnetic radiation travels as waves through space at the speed of light and includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays. 2. Wavelength is the distance between peaks of a wave and frequency is the number of waves passing a point per second. 3. The Bohr model describes atoms with electrons orbiting the nucleus in discrete energy levels, absorbing or emitting energy when changing orbits.

3. r

4. Electromagnetic spectrum

11. The electrons in the atom can make transitions between the orbits allowed by quantum mechanics by absorbing or emitting exactly the energy difference between the orbits

15. Quantum number l

16. Quantum number m

18. Hund’s diagonal Rule s 2 p 6 d 10 f 14

22. S