3 rd - Orbitals

1. 3rd- Orbitals

2. Orbitals • each sublevel is broken into orbitals • each orbital can hold a maximum of 2 electrons • orbital- a 3D region around the nucleus that has a high probability of holding electrons

3. Number of Orbitals sublevel max # e- # orbitals s p d f

4. One s orbital • spherical

5. Three p orbitals • dumbbell-shaped

6. Five d orbitals

7. Seven f orbitals

8. Energy # of Types of Level Row #s Sublevels Sublevels 1 2 3 4

10. 4th -Electron Configurations

11. Electron Configurations • the arrangement of electrons in an atom • each element has a unique electron configuration • electrons fill the lowest energy levels first • ground state electron configuration- lowest energy arrangement of electrons

12. Rules for Arrangements • Aufbau Principle- an electron occupies the lowest-energy orbital that can receive it • Beginning in the 3rd energy level, the energies of the sublevels begin to overlap

13. Rules for Arrangements • Pauli Exclusion Principle- no two electrons in the same atom can occupy the same place at the same time • Hund’s Rule- orbitals of a sublevel are each occupied by one electron before any orbital is occupied by a second • all unpaired electrons must have the same spin

14. Rules for Arrangements

15. Writing Configurations • Orbital Notation: • an orbital is written as a line • each orbital has a name written below it • electrons are drawn as arrows (up and down) • Electron Configuration Notation • number of electrons in sublevel is added as a superscript

16. Order for Filling Sublevels

17. Writing Configurations • How many e- in the atom? • What sublevel is the element in? • Draw out lines for each orbital beginning with 1s and ending with the sublevel identified • Add arrows individually to the orbitals until all electrons have been drawn

18. Silicon • number of electrons: 14 • last electron is in sublevel: 3p 1s 2s 2p 3s 3p • Valence Electrons- the electrons in the outermost energy level

19. 1s 2s Chlorine • number of electrons: 17 • last electron is in sublevel: 3p 2p 3s 3p

20. Sodium • number of electrons: 11 • last electron is in sublevel: 3s 1s 2s 2p 3s

21. Calcium • number of electrons: 20 • last electron is in sublevel: 4s 1s 2s 2p 3s 3p 4s

22. Bromine • number of electrons: 35 • last electron is in sublevel: 4p 1s 2s 2p 3s 3p 1s 2s 2p 3s 3p 4s 3d 4p 4s 3d 4p

23. Noble Gas Notation • short hand for larger atoms • configuration for the last noble gas is abbreviated by the noble gas’s symbol in brackets