1. Electrons

2. ATOMIC ORBITALS
Atomic Orbital: region of space in which there is a high probability of finding an electron.
Denoted by letters: s, p, d, and f
Each atomic orbital corresponds to a specific shape at a specific energy level.
s - spherical
p – dumbbell-shaped
d – clover leaf-shaped
f – more complex

3. ATOMIC ORBITALS Type of Sublevel Number of Orbitals
Number of Electrons s 1 2 p 3 6 d 5 10 f 7 14

4. ENERGY LEVELS & SUBLEVELS
Principle Energy Level
Number of Sublevels
Type of Sublevel
n=1 1
1s (1 orbital)
n=2 2
2s (1 orbital), 2p (3 orbitals)
n=3 3
3s (1 orbital), 3p (3 orbitals),
3d (5 orbitals)
n=4 4
4s (1orbital), 4p (3 orbitals),
4d (5 orbitals), 4f (7 orbitals)

5. MAXIMUM NUMBER OF ELECTRONS FOR EACH ENERGY LEVEL
Energy level (n)
Max number of Electrons 1 2 8 3 18 4 32

6. Energy Levels s Sublevels n = 1 n = 2 s p n = 3 s p d n = 4 f s p d
Nucleus s p d
n = 4 f s p d

7. Electron Configuration
The most stable arrangement of electrons in sublevels and orbitals.

8. A. General Rules Aufbau Principle
Electrons fill the lowest energy orbitals first.
“Lazy Tenant Rule”

9. A. General Rules Pauli Exclusion Principle
Each orbital can hold TWO electrons with opposite spins.

10. A. General Rules WRONG RIGHT Hund’s Rule
Within a sublevel, place one e- per orbital before pairing them.
“Empty Bus Seat Rule”
WRONG
RIGHT

11. 1s2 2s2 2p4 O B. Notation 1s 2s 2p 8e- Orbital Diagram
Electron Configuration
1s2 2s2 2p4

12. S 16e- 1s2 2s2 2p6 3s2 3p4 S 16e- [Ne] 3s2 3p4 B. Notation
Longhand Configuration
S 16e-
1s2
2s2
2p6
3s2
3p4
Core Electrons
Valence Electrons
Shorthand Configuration
S 16e- [Ne] 3s2 3p4

13. C. Periodic Patterns s p d (n-1) f (n-2) 1 2 3 4 5 6 7 6 7
© 1998 by Harcourt Brace & Company

14. C. Periodic Patterns Period # A/B Group # Column within sublevel block
energy level (subtract for d & f)
A/B Group #
total # of valence e-
Valence electrons are electrons in the outermost energy level. Determines the chemical and physical properties of an element.
Column within sublevel block
# of e- in sublevel

15. Bellwork – 10/4/16
Take a copy of the Magnetic Properties of Metals Lab
This will be turned in for a lab grade
Begin working on the electron configuration and orbital notation for the elements listed.

16. 1s1 C. Periodic Patterns 1st column of s-block 1st Period s-block
Example - Hydrogen
1s1
1st column of s-block
1st Period
s-block

17. C. Periodic Patterns p s d (n-1) f (n-2) Shorthand Configuration
Core e-: Go up one row and over to the Noble Gas.
Valence e-: On the next row, fill in the # of e- in each sublevel. s
d (n-1)
f (n-2) p

18. C. Periodic Patterns
Example - Germanium
[Ar]
4s2
3d10
4p2

19. Magnetic Spin
Remember Pauli’s Exclusion Principle – electrons fill orbitals with 2 electrons of opposite spins.
ms = +½
ms = -½
7.6

20. Paramagnetism and Diamagnetism
attracted to a magnetic field
unpaired electrons
Diamagnetism
Repelled by a magnetic field
Paired elecrons

21. 7.8 Paramagnetic Diamagnetic unpaired electrons all electrons paired

22. Determining Para/Diamagnetism
Substance is placed between electromagnets.
If the substance appears heavier, it is attracted in the magnetic field, and is paramagnetic.
If the substance appears lighter, it is diamagnetic.

23. D. Stability Full sublevel (s, p, d, f) Half-filled sublevel
Full energy level
Full sublevel (s, p, d, f)
Half-filled sublevel

24. D. Stability Electron Configuration Exceptions Copper
EXPECT: [Ar] 4s2 3d9
ACTUALLY: [Ar] 4s1 3d10
Copper gains stability with a full d-sublevel.

25. D. Stability Electron Configuration Exceptions Chromium
EXPECT: [Ar] 4s2 3d4
ACTUALLY: [Ar] 4s1 3d5
Chromium gains stability with a half-filled d-sublevel.

26. D. Stability 1+ 2+ 3+ 4± 3- 2- 1- Ion Formation
Atoms gain or lose electrons to become more stable.
Isoelectronic with the Noble Gases. 1+ 2+ 3+ 4± 3- 2- 1-

27. D. Stability O2- 10e- [He] 2s2 2p6 Ion Electron Configuration
Write the e- config for the closest Noble Gas
EX: Oxygen ion  O2-  Ne
The oxygen ion and Neon atom are isoelectric. The atom and ion have the same electron configuration.
O e [He] 2s2 2p6