# E h υ h j s useful equations c ? ν c 300 10 8 ms 1

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E = h × υ h = 6.63 × 10 -34 J · s useful equations c = λ × ν c = 3.00 × 10 8 m/s 1 m = 1 × 10 9 nm 1 kJ = 1000 J example Light with a wavelength of 525 nm is green. Calculate the energy in joules for a green light photon. - find the frequency: υ λ × = c λ c v = nm m nm s m v 9 8 10 1 1 525 / 10 00 . 3 × × × = s v / 1 10 71 . 5 14 × = - find the energy: υ × = h E ) / 1 10 71 . 5 )( 10 626 . 6 ( 14 34 s s J E × × = photon J E / 10 78 . 3 19 × = Problem-Solving Strategy Known Unknown Frequency ( ν ) Energy (E) Wavelength ( λ ) Frequency ( ν ) Energy (E) Energy (E) Frequency ( ν ) Wavelength ( λ ) Max Planck theorized that energy was transferred in chunks known as quanta , equal to h ν . The variable h is a constant equal to 6.63 × 10 -34 J · s and the variable ν represents the frequency in 1/s. This equation allows us to calculate the energy of photons, given their frequency. If the wavelength is given, the energy can be determined by first using the wave equation (c = λ × ν ) to find the frequency, then using Planck’s equation to calculate energy. Use the equations above to answer the following questions. 1. Ultraviolet radiation has a frequency of 6.8 × 10 15 1/s. Calculate the energy, in joules, of the photon. 2. Find the energy, in joules per photon, of microwave radiation with a frequency of 7.91 × 10 10 1/s. 3. A sodium vapor lamp emits light photons with a wavelength of 5.89 × 10 -7 m. What is the energy of these photons? 4. One of the electron transitions in a hydrogen atom produces infrared light with a wavelength of 7.464 × 10 -6 m. What amount of energy causes this transition? 5. Find the energy in kJ for an x-ray photon with a frequency of 2.4 × 10 18 1/s. 6. A ruby laser produces red light that has a wavelength of 500 nm. Calculate its energy in joules. 7. What is the frequency of UV light that has an energy of 2.39 × 10 -18 8. What is the wavelength and frequency of photons with an energy of 1.4 × 10 -21 J? J? Planck’s Equation Chem Worksheet 5-2 λ ν c = ν h E = h E = ν ν h E = λ ν c = Name __________________ Period ______
* This is an abbreviated configuration. A noble gas (element from group 18 of the periodic table) is written in brackets to represent a set of electrons. Then those that follow are written. 1 s 2 s 2 p Se: 3 s 3 p 4 s 3 d Each orbital is half-filled before being completely filled. Two electrons in the same orbital must have opposite spin. Electrons fill the lowest available energy levels first. This violates Hund’s rule. One electron should be distributed to each of the 3p orbitals before doubly filling any. 1 s 2 s 2 p 3 s 3 p Boxes drawn for various sublevels s sublevel: 1 orbital p sublevel: 3 orbitals d sublevel: 5 orbitals f sublevel: 7 orbitals 1 s 2 s 2 p 3 s 3 p 4 s 1 s 2 s 2 p 3 s 3 p 1 s 2 s 2 p 3 d 5 s 5 p 4 d 1 s 2 s 2 p 3 s 3 p 4 s 1 s 2 s 2 p 3 s 3 p 4 s 4 p 3 d An orbital diagram uses boxes with arrows to represent the electrons in an atom. Each box in an orbital diagram represents an orbital. Orbitals have a capacity of two electrons. Arrows are drawn inside the boxes to represent electrons. Two electrons in the same orbital must have opposite spin so the arrows are drawn pointing in opposite directions. The following is an orbital diagram for selenium. In writing an orbital diagram the first step is to determine the
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