Chem 111
Ch
L t
Lecture
24
UMass- Amherst
6 6 6 Biochemistry
6 6 2 ...Teaching
Initiative
Homework
• Continue Reading Chapter 7
• Owl Homework
- 6 6 6 6 6 2 ... 2
Recap
• Electron Configuration
• Pauli
P li exclusion
l i principle
i i l
• Effective Nuclear Charge
• Hund’s Rule
- 6 6 6 6 6 2 ... 3
Let’s Practice
Draw the orbital diagram representation for the electron
configuration of oxygen. What is its electron configuration?
- 6 6 6 6 6 2 ... 4
Magnetism
Paramagnetism: is caused by the presence of at least one
unpaired electron orbital (i.e., an unpaired spin) in the
atoms, molecules, or ions. Attracted to magnets.
Diamagnetism: is caused when all electrons are paired.
Slightly repulsed by magnets.
- 6 6 6 6 6 2 ... 5
Neon & Sodium
Valence Electrons: the outer shell electrons
Core Electrons: the inner shell electrons
- 6 6 6 6 6 2 ... 6
D-block
- 6 6 6 6 6 2 ... 7
Heavy Elements
- 6 6 6 6 6 2 ... 8
Periodic Table… again
- 6 6 6 6 6 2 ... 9
Let’s Practice
What is the characteristic outer shell electron configuration of
the group 7A elements, the halogens?
- 6 6 6 6 6 2 ... 10
Atomic Radii
- 6 6 6 6 6 2 ... 11
Ionization energy
ƒ Ease in which an electron can be removed
ƒ A(g) ÆA+(g) + e-(g)
Na(g) ÆNa+(g) + e-(g)
ƒ I = E(A+) – E(A)
ƒ First Ionization Energy, I1
ƒ Second Ionization, I2
Na+(g) ÆNa2+(g) + e-(g)
I1 < I2 < I3
- 6 6 6 6 6 2 ... 12
Electron Configuration of Ions
ƒ Sodium
N [1
Na:
[1s22s
2 22p
2 63s
3 1] Æ Na
N +: [1s
[1 22s
2 22p
2 6] + eƒ Germanium
Ge: [Ar]3d104s24p2 Æ Ge2+:[Ar]3d104s2 + 2eƒ Iron
Fe: [Ar]3d64s2 Æ Fe2+:[Ar]3d6 + 2eFe: [Ar]3d64s2 Æ Fe3+:[Ar]3d5 + 3e-
- 6 6 6 6 6 2 ... 13
Ionization energy
- 6 6 6 6 6 2 ... 14
Electron affinity
ƒ Ease in which an electron can be added
ƒ A(g) + e- (g) Æ A- (g)
Cl(g) + e- (g) Æ Cl- (g)
ƒ Ea = E(A) – E(A- )
ƒ The more negative Ea the easier it is to put an electron on to
the atom.
- 6 6 6 6 6 2 ... 15
Electron affinity
- 6 6 6 6 6 2 ... 16
Summary of Trends
- 6 6 6 6 6 2 ... 17