1. Homework for Tomorrow Fill in the chart on the following slide Fill in the chart on the following slide Do this on a single piece of notebook paper Do this on a single piece of notebook paper You MAY use a half sheet of paper but the chart can’t be any smaller than that You MAY use a half sheet of paper but the chart can’t be any smaller than that

2. Bell Work Principle Energy Level Sublevel( s) Orbital(s)# of electrons n=11s 1s- one orbital 1s- 2 electrons

3. Electron Configurations

4. Electron Configuration - distribution of electrons among the orbital's of an atom

5. Electron Configurations are determined by: distributing the atom’s electrons among: distributing the atom’s electrons among: (Using a set of stated principles) ---levels ---sublevels ---orbitals

9. Ground State electrons occupy lowest energy orbitals available to them electrons occupy lowest energy orbitals available to them most stable, lowest energy state of an atom most stable, lowest energy state of an atom This is how e’s normally exist This is how e’s normally exist

10. Three Principles for Electron Configurations 1. Aufbau Principle – electrons added 1 at a time to lowest energy orbital available

11. 2. Pauli Exclusion Principle – An orbital can hold a maximum of 2 electrons and they must have opposite spins.

12. 3. Hund’s Rule – Electrons will occupy equal-energy orbitals so that a maximum number of unpaired electrons results Ex: 2p orbitals

13. Orbital Diagram ---shows the locations of the e’s according to the 3 principles

16. Orbital Diagrams

17. Fe How many electrons do we need? ENERGYENERGY 1s 2s 2p 3s 3p 4s 3d

18. Ca How many electrons do we need? ENERGYENERGY 1s 2s 2p 3s 3p 4s

19. Be How many electrons do we need? ENERGYENERGY 1s 2s

20. Mg How many electrons do we need? ENERGYENERGY 1s 2s 2p 3s

21. P How many electrons do we need? ENERGYENERGY 1s 2s 2p 3s 3p

22. How to write an electron configuration 1. Determine # of electrons in atom or ion 2. Using arrow chart, start placing electrons in the lowest energy sublevels (remember the rules)

23. REMEMBER…. S’s – only 2 electrons S’s – only 2 electrons P’s – only 6 electrons P’s – only 6 electrons D’s – only 10 electrons D’s – only 10 electrons F’s – only 14 electrons F’s – only 14 electrons

25. Practice 1. Carbon 2. Argon 3. Mn 4. Radon

26. How to do an abbr. electron conf: 1. Determine the number of electrons 2. Find the noble gas (last column) that is closest to your element but that has less electrons

27. 3. Write the symbol for that noble gas in square brackets (ex: [Ne]) 4. After the [ ] continue the configuration like normal

28. C 1s 2 2s 2 2p 2. C 1s 2 2s 2 2p 2. Na 1s 2 2s 2 2p 6 3s 1. Na 1s 2 2s 2 2p 6 3s 1. P 1s 2 2s 2 2p 6 3s 2 3p 3. P 1s 2 2s 2 2p 6 3s 2 3p 3. Br 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5. Br 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5. Cd 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10. Cd 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10. Abbreviated Electron Configuration Use the noble gas from the row above your element then add the rest of the configuration [He] [Ne] [Ar] [Kr]

30. Arrow Chart