Ap Chemistry Due Next Class: Reading 6.5-6.8 & Proof of reading Hand Warmer LaB Up Coming Due Dates: MC Ch. 6 Due… DON’T PROCRASTINATE!

Hand Warmer Lab Report Requirements Objective Materials General Procedure Data Questions Proposal & Justification

Warm Up Most missed on Ch. 5 MC

Lecture 6.1-6.4

Electronic Structure The distance between corresponding points on adjacent waves is the wavelength (). The number of waves passing a given point per unit of time is the frequency ().

Electromagnetic Radiation You listen to in your car Cancer Radiation Therapy Cooks your food All electromagnetic radiation travels at the speed of light (c) 3.00  108 m/s. c =  Careful! Wavelength is in nm and c is in m/s This is what we will mainly be looking at

The Photoelectric Effect Energy comes in packets called quanta (singular: quantum). Einstein used quanta to explain the photoelectric effect. Each metal has a different energy at which it ejects electrons. At lower energy, electrons are not emitted. E = h Planck’s constant Frequency https://phet.colorado.edu/en/simulation/photoelectric

The energy of a photon divided by its frequency equals c, the speed of light. h, Planck’s constant. Avogadro’s Number. 4.184. Answer: b

Continuous vs. Line Spectra Continuous spectrum (the “rainbow” is from white light Line spectrum- Discrete wavelengths is observed. Each element has a unique line spectrum. Each element is QUANTIZED!

Bohr + Planck’s Ideas = Electrons can only occupy certain orbits (corresponding to certain energies). Electrons have specific, “allowed” energies Energy is only absorbed or emitted to move an electron from one “allowed” energy state to another; E = h

The lowest energy state of a hydrogen atom is called its _______ state. bottom ground fundamental original Answer: b

Limitations of the Bohr Model It only works for hydrogen! Classical physics would result in an electron falling into the positively charged nucleus. Bohr simply assumed it would not! Circular motion is not wave-like in nature.

Important things of the Bohr Model Nobel prize for me! Electrons exist only in certain discrete energy levels. Energy is involved in the transition of an electron from one level to another.

The Uncertainty Principle Heisenberg Uncertainty Principle: The more precisely the momentum of a particle is known, the less precisely is its position is known… Nobel prize for me too! (x) (mv)  h 4

Work time 6.1-6.4 Practice Lab Work Time due next class!