Electron Configuration and Periodic Trends Overview

Electron Configuration

________________ is the distribution of electrons in atomic orbitals

Ground State

___________ is the lowest energy state of an atom

Aufbau Principle

The _______________ states that electrons start to fill in from the lowest energy orbital available

- S orbital

- p orbital

- d orbital

- f orbital

Aufbau Principle:

What are the 4 main orbitals discussed in lecture?

S orbital → L = 0 1 orbital 2 electrons

p orbital → L = 1 3 orbitals 6 electrons

d orbital → L = 2 5 orbitals 10 electrons

f orbital → L = 3 7 orbitals 14 electrons

Aufbau Principle:

What is the L- value for the s, p, d and f orbital?

how many orbitals and electrons does each have?

True

True or False:

The Aufbau Principle states ->

As n increases, the number of orbitals increase (energy of orbitals increase)

False, As L increases, the energy of orbitals increase

True or False:

The Aufbau Principle states ->

As L decreases, the energy of orbitals increase

orbitals

The number of ___________ accounts for the number of spaces in orbital diagrams

1. 3 spaces

2. 5 spaces

3. 1 space

4. 7 spaces

The number of orbitals accounts for the number of spaces in orbital diagrams. How many spaces would there be for

1. p orbitals

2. d orbitals

3. s orbitals

4. f orbitals

1. 1s^1

2. 1s^2

3. 1s^2 2s^1

4. 1s^2 2s^2

5. 1s^2 2s^2 2p^1

6. 1s^2 2s^2 2p^4

What is the electron configuration for ->

1. H (hydrogen)

2. H (helium)

3. Li (lithium)

4. Be (Beryllium)

5. B (Boron)

6. O (oxygen)

1. P → [Ne] 3s^2 3p^3

2. O → [He] 2s^2 2p^4

3. Br → [Ar] 4s^2 3d^10 4p^5

4. W → [Xe] 6s^2 4f^14 5d^4

Use Noble gas abbreviations to find the electron configuration for ->

1. P (phosphorus)

2. O (oxygen)

3. Br (bromine)

4. W (Tungsten)

Hund's Rule

___________ states that when filling orbitals of equal energy (degenerate) we fill orbitals to give the max number of the unpaired electrons

Orbital diagrams

Hund's rule is shown in _______________

↑↓ - opposite arrows

The ___________ in an orbital diagram relates to the spin (1/2 and -1/2)

Orbital diagrams

_________________ can be used to determine whether an element is diamagnetic or paramagnetic.

Diamagnetic

Orbital diagrams that are _____________ have all paired electrons and are not attracted to the magnetic feild

Paramagnetic

Orbital diagrams that are ____________ contain unpaired electrons and are attracted to the magnetic field

[Ne] ↑↓ ↑ ↑

— — —

3s 3p

Paramagnetic

What is the orbital diagram for P? Is P paramagnetic or diamagnetic?

[Ar] ↑↓ ↑ ↑ ↑ ↑ ↑

— — — — — —

4s 3d

What is the orbital diagram for Fe?

[Ar] ↑ ↑ ↑ ↑ ↑ ↑

— — — — — —

4s 3d

What is the orbital diagram for Cr?

Zn → [Ar] 4s^2 3d^10

[Ar] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓

— — — — — —

4s 3d

diamagnetic

What is the electron configuration and orbital diagram for Zn? Is Zn paramagnetic or diamagnetic?

Zn^2+ → [Ar] 3d^10

[Ar] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓

— — — — —

3d

What is the electron configuration and orbital diagram for Zn^2+?

a. 1-2

b. 13-18

The main group elements belong to groups ______ and ______

Isoelectronic

Atoms or ions with identical electron configurations are considered to be ________________

False

Na+ F- and Ne all have the same electron configurations, making them isoelectronic

True or False

Na+ F- and Ne have different electron configurations, making them isoelectronic

a. 1-2

b. 14-17

a. Groups ___________ tend to lose the outer electrons to form cations

b. Groups __________ tend to gain electrons in the outer p subshell

Stability

Complete shells have increased _____________ making it difficult to add and remove electrons

Transitional metals (groups 3-12)

______________ are elements that can form multiple cations (positive ions)

Transitional metal cations (groups 3-12) are formed by removing s electrons before d electrons

How are Transitional metal cations formed?

False

d electrons are lower in energy than s electrons, making s electrons the first to go

True or false:

s electrons are removed before d electrons when forming a Transitional metal cation because d electrons are higher in energy than s electrons

Valence electrons

_____________ are the highest energy electrons

Core electrons

____________ are electrons not involved in bonding - they shield valence electrons (valence electrons do not shield each other very well)

1. Effective nuclear charge (Z_eff)

2. n-level (of valence electrons)

What are the two periodic trends discussed in lecture?

Z_eff (Effective nuclear charge) Periodic Trend

The __________ periodic trend Increases L -> R and decreases R -> L across a period

n-level Periodic Trend

The ___________ periodic trend increases T -> B and decreases B -> T

Z_eff (increases L -> R)

Periodic Trend:

As ___________ increases, the valence electrons are held more tightly to the nucleus (are more attracted to the nucleus)

n-level (increases T-> B)

Periodic Trend:

As _____________ increases, the valence electrons are held further from the nucleus, making them less attracted to the nucleus (held less tightly to the nucleus)

- Z_eff - L -> R (closer to the nucleus)

- n-level - T -> B (further from the nucleus)

Periodic Trend:

Atomic/Ionic size (radius) decreases as __________ increases from __________

Atomic/Ionic size (radius) Increases as ___________ increases from ___________

Positive

The more ___________ the IE (Ionization energy), the harder it is to remove valence electrons (electrons held more tightly to nucleus)

- Z_eff

- L -> R (more attracted to the nucleus)

Periodic Trend:

Ionization energy (IE) becomes more positive as ______________ increases from ___________

- n-level

- T -> B (less attracted to the nucleus)

Periodic Trend:

Ionization energy (IE) becomes less positive as ___________ increases from ___________

Ionization Energy (IE)

_______________ is the energy required to remove a valence electron from an atom or Ion in its gaseous (g) state

Electron Affinity (EA)

_____________ is the energy change when adding an electron

Negative

The more ___________ the Electron Affinity (EA), the more favorable it is to add an electron

- Z_eff

- L -> R (more attracted to the nucleus)

Periodic Trend:

Electron Affinity (EA) becomes more negative/favorable as ____________ increases from _________

- n-level

- T -> B (less attracted to the nucleus)

Periodic Trend:

Electron Affinity (EA) becomes less negative/favorable as __________ increases from ___________

1. Be > Li > Na

2. Li is greater than Na because the valence electrons are held at a lower n-level (T → B) that is closer to the nucleus, making it held more tightly to the nucleus

Be is greater than Li because its Z eff is greater (L → R), so its electrons are held more tightly and therefore are harder to remove

1. Rank Na, Li, and Be from highest to lowest based of Ionization energy (IE)

2. Explain your answer

1. F < O < S

2. F is smaller than O because F has a greater Z eff (L → R), which causes the valence electron to be held more tightly to the nucleus

O is smaller than S because its valence electron in O are in a lower n-level (T → B) which makes them closer to the nucleus

1. Rank S, O, and F from smallest to biggest based on atomic size

2. Explain your answer