Name Period CRHS Academic Chemistry Unit 4 Electrons Practice Problems Due Date Assignment On-Time (100) Late (70) 4.1 4.2 4.3 4.4 4.5 Warm-Up EC Notes, Homework, Exam Reviews and Their KEYS located on CRHS Academic Chemistry Website: https://cincochem.pbworks.com
Page 2 of 12 Unit 6 HW WARM-UPS Day 1 Day 7 Day 2 Day 8 Day 3 Day 9 Day 4 Day 10 Day 5 Day 11 Day 6 Day 12
HW 4.1 WAVE NATURE OF LIGHT Unit 6 HW Page 3 of 12 1) All light consists of electromagnetic waves. Visible light is only a small portion of the electromagnetic spectrum. List four types of light from the electromagnetic spectrum. a) b) c) d) 2) Match each term describing waves to its definition. Amplitude wavelength frequency f a. the distance between two crests b. a wave s height from the origin to the crest c. the number of wave cycles to pass a given point per unit of time 3) Match each term with its units. Amplitude wavelength frequency f a. Hertz (Hz) or cycles per second b. displacement (metric measurement nm, m, km) c. distance (metric measurement nm, m, km) 4) Label the parts of a wave in this drawing, including wavelength, amplitude, crest, trough, and origin.
Page 4 of 12 Unit 6 HW 5) ( TRUE / FALSE ) The frequency and wavelength of any wave are inversely related. 6) The product of frequency and wavelength of any wave of light always equals the, whose symbol is. 7) What is the wavelength of radiation with a frequency of 1.50 x 10 13 Hz? 8) After injuring her knee during a softball game, Caitlyn sees her doctor who recommends imaging of her knee to assess for damage to the bony structures in that area. The doctor orders 3 different x-ray images from different points of view. The x-ray the radiologist chooses has a wavelength of 1.15 x 10 10 m. What is the frequency of this form of light? 9) An unknown type of electromagnetic radiation has a frequency of 7.8 x 10 16 Hz. First, find the wavelength of this interesting bit of light. Then, decide which type of light it most closely resembles (hint: look at the electromagnetic spectrum in your notes)
HW 4.2 PARTICLE NATURE OF LIGHT Unit 6 HW Page 5 of 12 1. Planck and Einstein showed mathematically that the amount of radiant energy (E) absorbed or emitted by a body is (DIRECTLY / INVERSELY) related to the frequency of the radiation: E = hf. 2. Label all parts of the Energy equation give the units for energy and frequency: E = h x f 3. A radio wave has a frequency of 1.13 x 10 4 Hz. How much energy does this wave have? 4. The sun emits cosmic radiation with a frequency of 5.12 x 10 21 Hz. How much energy do they contain? 5. How much energy is produced by a light with a wavelength of 3.53 x 10-9 m? 6. An Argon Gas-Ion laser has a wavelength of 1.09 x 10-10 m, how much energy does this laser have?
Page 6 of 12 Unit 6 HW 7. A small, discrete unit of energy is called a. 8. What did Albert Einstein call the quanta of energy that is light? 9. What is the photoelectric effect? 10. Passing the light emitted by an element through a prism gives the of the element. 11. The lowest energy level of an electron is called its. 12. Only electrons in transition from ( LOWER / HIGHER ) to (LOWER / HIGHER ) energy levels lose energy and emit light. 13. Electrons behave as both and. 14. ( TRUE / FALSE ) Electrons can exist between energy levels. 15. A quantum of energy is the amount of energy required to a. move an electron from its present energy level to the next lower one b. maintain an electron in its present energy level c. move an electron from its present energy level to the next higher one
HW 4.3 ELECTRON CLOUD: QUANTUM MODEL Unit 6 HW Page 7 of 12 1) In the quantum model, electrons are identified by 4 Quantum Numbers that describe their position and properties in the electron cloud. Their names are listed below. Provide description of what they represent. Primary Energy Level (n) - Angular Momentum (l) - Magnetic Quantum Number (m) - Spin (-/+) 2) How many energy levels can an atom contain? 3) List the 4 sublevels and fill in the rest of the table: SUBLEVEL Shape # of orbitals in sublevel 4) How many electrons can an orbital hold?
Page 8 of 12 Unit 6 HW HW 4.4 ELECTRON CONFIGURATION 1) Describe the Aufbau Principle - 2) In an electron configuration, what does a superscript stand for? 3) In an electron configuration, what does the sum of all the superscripts equal? 4) Fill in this table: Element Electron Configuration 1s 1 B 1s 2 2s 2 2p 6 3s 2 3p 3 C 1s 2 2s 2 2p 3 Cl 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 Ne 5) Examine the following electron configurations on the next page. Identify the elements. a) 1s 2 2s 2 b) 1s 2 2s 2 2p 6 3s 2 3p 1 c) [Xe] 54 6s 2 4f 14 5d 10 d) 1s 2 2s 2 2p 3 e) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 f) [Kr] 36 5s 2 g) 1s 2 2s 2 2p 6 3s 2 3p 6
h) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 Unit 6 HW Page 9 of 12 i) [Ar] 18 4s 2 3d 2 j) 1s 2 2s 2 2p 6 3s 2 6) The following electron configurations are INCORRECT. Write why each of these is NOT POSSIBLE. a) 1s 2 2s 2 3s 2 b) 1s 2 2s 2 2p 2 3s 1 c) 1s 2 2s 2 2p 6 2d 5 7) Write the noble gas configuration for the following atoms. a) Sodium b) Potassium C) Strontium
Page 10 of 12 Unit 6 HW HW 4.5 ORBITAL NOTATION 1. Describe the Hund Rule - 2. Describe the Pauli Exclusion rule - 3. How many electrons are in an atom of calcium? What is the atomic number of calcium? Write the complete orbital notation for calcium. 4. How many electrons are in the 3 rd energy level of a bromine atom? What is the highest occupied energy level of bromine? Write the complete orbital notation for bromine. 5. Fill in the table: Element Electron Configuration Orbital Notation B C O Ne 1s 2s 1s 2s 2p
Unit 6 HW Page 11 of 12 6. Consider the following orbital notations for phosphorus. Circle the correct orbital notation AND explain what is wrong with the other 3 orbital notations. a) 1s 2s 2p 3s 3p b) 1s 2s 2p 3s 3p c) 1s 2s 2p 3s 3p d) 1s 2s 2p 3s 3p
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