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Unformatted text preview: While you wait, please try the following problems: # electrons # neutrons # protons Shorthand Sn 118 Cu 2+ 64 O 17 H 1+ 1 Determines the identity element With #p, determines mass number With #p, determines the charge 50 68 50 35 29 8 9 27 10 1 50 29 8 1 2 Light exists as a wave Waves come in all different sizes and colors Long wavelength Short Wavelength Wavelength = λ Section 2.1 Frequency So we can measure a wave’s frequency ( ν ) , or how many waves pass a given point in one second frequency ( ν ) = # waves/sec All light waves travel at the same speed, the speed of light (c) Section 2.1 Shorter Wavelength → HIGHER FREQUENCY ( more waves/sec) Section 2.1 Frequency Longer Wavelength → LOWER FREQUENCY ( less waves/sec) Long Wavelength = Low Frequency Short Wavelength = High Frequency c = λ ν c is the speed of light (m/s) λ is wavelength (m) ν is frequency (s1 or hertz) Section 2.1 Wavelength and Frequency speed = (wavelength)(frequency) constant! So, if you know wavelength, you know frequency and vice versa! The energy of the light depends on the frequency or wavelength of its wave E= h ν E= hc /λ E = Energy (J) h = Plank’s constant (J*s) ν = frequency (s1 ) c = speed of light (m/s) λ = wavelength (m) Section 2.1 Wave Energy Energy = (constant)(frequency) = (constant)(speed)/(wavelength) Section 2.1 Wave Energy Long wavelength Low Frequency Low ENERGY Short wavelength High Frequency High ENERGY ν 10 6 Radio 10 10 10 14 10 20 micro infrared vis UV Xrays γ There is a continuum of light shown below, the electromagnetic spectrum. n=4 n=3 n=2 # nodes = n  1 node node node node node node n=1 (2) (1) (0) (3) The more nodes, the higher the energy! Section 2.4 Waves and Nodes node node n=3 L = 1 / 2 n λ λ = 2L/n = 2 / 3 L L λ # nodes = n – 1 = 2 Waves and Nodes Section 2.4 + What needs to happen when we add energy to a H atom? Nucleus Increasing r Increasing E When an H atom absorbs energy, its electron must move farther away from the nucleus. Recall Coulomb’s Law: E = q 1 q 2 ε r = (+1)(1) = 1 Constant Increasing E causes absolute value of the right side to get smaller . So, r must get bigger. Section 2.2 Adding Energy to an Atom Is it that simple?...
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 Fall '08
 BIGHAM
 Atom, Electron, Proton, Energy, Wavelength, Pauli exclusion principle, Wave Energy

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