1. Labeling Electrons in Atoms

2. 2) Three numbers give the location of the electrons. The forth describes the spin of the electron. 3) The first quantum number, is principal quantum number, represented by the letter n. 4) Describes main energy level occupied by the electron Same as periods of periodic table 5) n= 1 is the lowest energy level (e - ’s here have lowest energy) 1) In quantum theory, each electron is assigned a set of 4 quantum numbers

3. 6) Quantum numbers also describe the shape of atomic orbitals. 2 nd quantum number is the angular momentum quantum number, l. 7) usually expressed as letters rather than numbers l valueLetter value 0s 1p 2d 3f Sublevels

4. 8) Lowest energy orbital in each energy level = 0 (aka s orbital). It has a sphere shape. Only one s orbital is allowed in each energy level ** s orbital electrons (s – block) found in Group 1 & 2, & He ** *** s orbitals can hold a max of 2 electrons*** l valueLetter valueShape 0ssphere 1p 2d 3f

5. 9) Next, the p orbital has a higher energy than s In each energy level (beginning at n = 2) there are 3 p orbitals *** p orbital electrons found in Group 13 - 18) *** *** p sublevel can hold a total of 6 electrons*** l valueLetter valueShape 0ssphere 1pdumbbell 2d 3f

6. Check Point #1 Which of the following quantum numbers is often designated by the letters s, p, d, and f instead of by numbers? A. n B. l C. m D. s

7. Check Point #1 Which of the following quantum numbers is often designated by the letters s, p, d, and f instead of by numbers? A. n B. l  C. m D. s

8. 10) d & f orbitals Beginning at n = 3, there are now 5 d orbitals & At n = 4, there are now 7 f orbitals *** d orbital e - s found in Groups 3 – 12 (transition metals)*** *** f orbital e - s are found in Lanthanide and Actinide series** l valueLetter valueShape 0ssphere 1pdumbbell 2dclover 3f-

9. In n = 1, how many sublevels (different kinds of shapes) are found? In n = 2, how many sublevels can be present? How many p orbitals can be found in an energy level? How many electrons can any single orbital hold?

10. 11) The third quantum number, magnetic quantum number, m, tells orientation of the orbital around the nucleus

11. 13) The fourth quantum number, spin quantum number, tells us of any single can hold a maximum of 2 electrons with opposite spins Value of + ½ and – ½ 14 & 15) No two electrons have an identical set of 4 quantum numbers in the same atom. **This is the Pauli exclusion principle. 16) There is a maximum number of electrons allowed in each energy level and orbital.

12. n sublevels n

13. Check Point #2 What is the maximum number of electrons that can occupy a 3s orbital? A. 1 B. 2 C. 6 D. 10

14. Check Point #2 What is the maximum number of electrons that can occupy a 3s orbital? A. 1 B.2  C. 6 D. 10