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Intro to Electron Configuration. Objective Today I will be able to: Calculate the electron configuration for elements on the periodic table Evaluation/ Assessment
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Objective • Today I will be able to: • Calculate the electron configuration for elements on the periodic table • Evaluation/ Assessment • Informal assessment – student responses when reviewing electron configuration problems. Listening to group interactions on practice sheets and lab • Formal Assessment – collecting and analyzing responses to electron configuration worksheet 2
Lesson Sequence • Warm – Up • Explain: How to write electron configurations • Elaborate: write electron configurations with a partner for questions 1-18 • Evaluate: review the questions as a class (informal assessment) • Explain: electron configurations in 3d orbitals and Aufbau diagrams • Elaborate: Students will complete 19-36 on electron configuration WS with a partner • Evaluate: review the questions as a class (informal assessment) • Explain: abbreviated electron configurations • Elaborate: Students will add a column to the WS and repeat write the abbreviated configuration • Evaluate: Abbreviated configurations will be reviewed as a class (informal assessment) • Exit Ticket
Warm - Up • What is an electron? • What is the abbreviation for an electron? • How does the mass of an electron compare to the other subatomic particles? • Do you believe in electrons? • How do we know electrons exists and how they move and behave?
Objective • Today I will be able to: • Calculate the electron configuration for elements on the periodic table
Homework • Electron Configuration Practice
Agenda • Warm – Up • Halloween Demos (as promised) • Electron Configuration Notes • Electron Configuration Practice • Exit Ticket
Electron Configuration • Electron configuration – arrangement of electrons in an atom • Electrons try to populate the lowest energy levels available – “ground state”
Arrangement of Energy Levels • Principal energy levels – represented by n • As atoms get bigger, there are more electrons, therefore more energy levels • Within each energy level, we have one or more sublevels • These sublevels are made up of orbitals
Orbitals • According to modern atomic theory electrons are found in orbitals • Orbital – 3-D region around the nucleus indicating the probable location of the electron • There are 4 types of orbitals where the electrons can be found – s,p,d,f • Order of energy from lowest to highest: • s, p, d, f
Energy Sublevels • Each sublevel occupies a specific location on the periodic table:
Electron Configuration n 1 2 3 4 5 6 7 p-block s-block d-block n-1 f-block n-2
Orbitals cont. • Each sublevel can hold a specific amount of electrons • S=2 • P=6 • D=10 • F=14
Electron Configurations • We can write the electron configurations for each element (assuming the atom has a neutral charge) representing the location of the elements electrons in the energy levels
Examples • Sodium (Na) • Has 11 electrons (when neutral) • Electron Configuration: • 1s22s22p63s1 • Cobalt (Co) • Has 27 electrons (when neutral) • Electron Configuration • 1s22s22p63s23p64s23d7
Electron Configuration Practice Complete numbers 1-18
Why does 4s come before 3d? • 3d is of slightly higher energy than 4s, but 4s is further from the nucleus • It takes less energy for a 3d electron to form pairs then a 4s electron
Aufbau Diagram • Instead of using the periodic table as a road map, you can use the aufbau diagram to determine the order that the electrons occupy the different energy levels • Electrons fill the lowest energy orbitals first
Abreviated Electron Configuration • Scientists are lazy ;) • We need a shorthand way to represent electron configuration • It would take a long time to write the configuration for elements with a lot of electrons • How do we do this? • Noble Gas Configuration
Noble Gas Configuration • The last column on the periodic table is referred to as the noble gases • To write in abbreviated configuration: • Find the last noble gas within the configuration • Write the symbol • Write the remaining configuration • Example • Ca - 1s2 2s2 2p6 3s2 3p6 4s2 • Noble Gas Configuration = [Ar] 4s2
Noble Gas Configuration • Writing Noble Gas Configurations for ions is a little bit different • Must account for an electron being gained or lost • Chlorine Ion = Cl-1 • [Ne] 3s2 3p6 • Sodium Ion = Na+1 • [He] 2s2 2p6
Electron Configuration Practice Go back and write the Abbreviated (Noble Gas) configuration for the elements on the worksheet on the right hand margin
Exit Ticket • Write the electron configuration of sulfur