1. Physics and the Quantum Mechanical Model

2.  Light consists of waves  A wave cycle begins at zero, increases to its highest value (crest), returns to zero, decreases to its lowest value (crest) and then returns to zero  The amplitude of the wave is the distance between zero and its crest  The wavelength ( λ) is the distance between the two crests  The frequency ( ν) is the amount of waves occurring per unit of time The time frame is usually the second The SI units of frequency for cycles per second is the hertz (Hz)

3. c = λν c = 2.998 x 10 8 m/s  Wavelength and frequency are inversely proportional to each other  As one increases, the other must decrease in order for the speed of light to remain a constant

4.  Electromagnetic radiation includes radio waves, microwaves, infrared, visible light, X-rays, UV and gamma rays  Sunlight has a continuous range of wavelengths and frequencies  Each colour on the spectrum has its own unique frequency Red has the longest wavelength and lowest frequency

5.  Passing electricity through a gas tube causes electrons to move from one orbital to the next  When they absorb energy, the move from an inner orbital to an outer one  They emit light when they move back to the inner orbital  An atomic spectrum can be considered to be the ‘fingerprint’ of an element

6.  An e- in its lowest possible energy level is in a ground state  The light emitted from the e- as it moves from a higher energy state to a lower one has a frequency directly proportional to the energy change of the e-

7.  The amount of energy required for the e- to move can be described as quanta of energy Quanta behave as though they are particles Light quanta are called photons  Matter(which is constantly moving) can behave like waves of energy

8.  Heisenburg said that e- are incredibly small and occupy a large area around the nucleus  It is impossible to know both the velocity and position of a particle at the same time  Figure 5.16, page 145