1. Electron Configuration Chapter 5 Section 3

2. 1. You need this to see! Sodium + Titanium + Rhenium 2. You or me Sulfur + Nitrogen + Phosphorous + Oxygen + Erbium 3. Vacation home Calcium + Indium + Boron 4. Don’t gamble on this one! Erbium + Polonium + Potassium

3. Electron Configuration  Electron Configuration – the arrangement of electrons in an atom  Electrons tend to assume the arrangement that gives them the lowest energy possible, due to the fact that low energy systems are more stable  Three Rules to follow: Aufbau principle; Pauli exclusion principle; and Hund’s Rule

4. Aufbau Principle  Each electron occupies the lowest energy orbital available

5. Pauli Exclusion Principle  A maximum of two electrons can occupy a single atomic orbital, but only if the electrons have opposite spins

6. Hund’s Rule  Single electrons with the same spin must occupy each equal-energy orbital before additional electrons with the opposite spin can occupy the same orbital

7. Which of the following is correct?

9. Using the periodic table as a key

10. What block/energy level do the following elements belong?  Ru  O  Br  Cs  Np  Ar  4d  2p  4p  6s  5f  3p

11. What is the electron configuration for Be?

12. What is the electron configuration for N?

13. What is the electron configuration for Mg?

14. What is the electron configuration for S?

15. What is the electron configuration for K?

16. What is the electron configuration for Ni?

17. Homework 10/27/14  Do the electron configuration for elements 1 – 18 in your notes.

18. Electron Configuration Notation  Designates the principal energy level, the energy sublevel (associated with each orbital), and the number of electrons in the sublevel  Sodium: ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑_ 1s 2s 2p 3s  Sodium: 1s 2 2s 2 2p 6 3s 1

19. Write the Electron configuration notation for the following:  Zr  Ce  Ni  Se  Sr

20. HW: Using your homework from last night write the notation for elements 1 – 18  H  He  Li  Be  B  C  N  O  F  Ne  Na  Mg  Al  Si  P  S  Cl  Ar

21. Noble Gas Notation  Noble gasses are the last column of the periodic table  Full p-shells = Very stable  Noble Gas Notation uses bracketed symbols to consolidate notation  Notation for Na: 1s 2 2s 2 2p 6 3s 1  Noble Gas Notation for Na: [Ne] 3s 1

22. Noble Gas Notation  Use the Noble gas before the element you are looking at  Start electron configuration after that noble gas  Example: For Mo, Kr ends in 4p 6 so you start with 5s  [Kr] 5s 2 4d 4

23. What is the noble gas notation for the following:  Bi  Rb  V  Si  Ru