Chemistry Study Notes - Electrons and Light

Essay by thekingandqueenHigh School, 10th grade March 2009

download word file, 4 pages 4.0 3 reviews

Electric and magnetic components to every light wave-speed of light is always constant-speed of light = wavelength x frequency (c = λv)Particle Nature of Light-matter can gain or lose energy only in small, specific amounts called quanta-a quantum is the minimum amount of energy that can be gained or lost by an atom-Equantum = hv-h is Planck’s constant and v is frequency-energy and wavelength are inversely related-for a given frequency matter can emit or absorb energy only in whole-number multiples of h-can’t use the wave description of light to explain this phenomenon (light energy is not wave like, but particle-like of specific sizes)-Photoelectric effect: when light is shone on a metal, electrons may be emitted by the metal-electrons absorb light energy which provides enough energy for theelectrons to leave the atom-the faster the electrons are moving, the more energy was transferredfrom the light-lower frequency (v) number of waves that pass through a point in space per second, s-1, 1/s, Hz --> longer wavelength (λ) meters, centimeters → lower energy-shorter wavelength --> higher frequency-if no electrons ejected --> minimum threshold energy required to eject an electron from the metal (light did not provide sufficient energy)-beam of light is a stream of tiny particles called photons-a photon is a particle of electromagnetic radiation with no mass that carries a quantum of energy-Ephoton = hv – h is still Planck’s constant and v is frequencyAtomic Emission Spectra-electrons absorb a photon (from light) or quantum of energy (from electricity), causing them to move further from the nucleus-to pull the electron away from the positive negativeattraction between the negatively charged electron and the positively charged nucleus --> needs energy-only very specific distances (electrons move farther away fromthe nucleus with quantized amounts of energy in multiples of h – Planck’s constant which represents a quantum)-this excited...