Electron Config / Periodic Table Trends Flashcards
1
Q
The Aufbau Rule
A
The lowest energy levels are filled first
2
Q
The Pauli Exclusion Principle
A
Orbitals can have max of 2 electrons e- in same orbital must have opposite spins
3
Q
Hund’s Rule
A
When orbitals of identical energy (same shape) are available, e- enter those orbitals singly before any spin pairing takes place
4
Q
Periodic Law
A
- Properties of elements are periodic functions (repeating patterns) of their atomic numbers
- Elements arranged in order of increasing atomic number, physical/chemical properties, repeat in predictable pattern
5
Q
Today’s periodic table
A
- Rows/periods: 7 rows, corresponding to the number of energy levels containing electrons in their ground state
- Columns/groups/families: 18 columns, 1A-8A (main group elements), correspond to # of valence electrons present in the element
6
Q
Metals
A
- Malleable
- Conductors
- Solid at room temp (except Hg)
- Give away e-
- Lustrous
7
Q
Nonmetals
A
- Brittle
- Insulators
- Solids, liquids, gases
- Take e-
- Dull
8
Q
Main group elements
A
- s and p blocks
- 1A-8A
- Most obvious ones to follow periodic law
- Not main:
- d block
- 1B, 2B, etc
9
Q
Effective nuclear charge
A
- The full charge of the nucleus is not experienced by the valence electrons because of the repulsion among the electrons
- The valence electrons are shielded by the core electrons
- The charge “felt” by the valence electrons is Zeff
- Bigger Zeff = stronger attraction between nucleus and valence electrons
10
Q
When does Zeff increase
A
- Increases across period
- Same shielding, more protons
- Decreases down a group
- More core e-
- More shielding/repulsion
11
Q
Zeff H and He
A
- H: high
- no core e-, shielding
- He: very high
- no core e-, no shielding
- higher than H b/c more protons
12
Q
Atomic radii
A
- Increases down a group
- More shielding, more repulsion, lower Zeff, lower attraction
- Decreases across a period
- same shielding, more P+, bigger Zeff, more attraction
13
Q
Atomic radii periodic trend chart
A
14
Q
Cation sizes
A
- Smaller than the atoms from which they came
- Electron/proton attraction has gone UP so size decreases
- Energy level decreases b/c losing e-
15
Q
Anion sizes
A
- Larger than the atoms from which they come
- Electron/proton attraction has gone down size increases
- Trends in ion sizes same as at
16
Q
Trends in ion sizes
A
- Cations smaller than ions
- Except Rb+1 and Cs+1 bigger or same size as F+1 and O-2
- Larger negative charge = larger anion
17
Q
Ionization energy
A
- IE = energy requires to remove an electron from an atom in the gas phase
- High Zeff = high IE
- Exceptions
- Based on trends, O’s IE > N’s IE
- N 2p: | | |
- O 2p: || | |
- O wanted to be half filled
18
Q
First IE trends
A
- Larger Zeff = more energy to remove e-
- Farther most probable distance the e- is from nucleus, less energy takes to remove it
- IE decreases down group
- Val e- farther from nucleus
- IE increases across period
- Zeff increases
20
Q
Successive ionization energy
A
- IE2 = energy required to remove the second electron from an atom in the gas phase
- Harder to pull e- from a + ion
21
Q
Predicting charge from IE
A
- Element 1
- Alkaline metals, group 1
- +1 charge
- Element 2
- Ga, Al, In, Sc
- +3 charge
