U1-2 - Atomic Orbitals, Electronic Configurations and the Periodic Table

Question 1

Principal quantum number, n

Answer 1

Energy level the electron resides in

Question 2

Angular momentum quantum number, l

Answer 2

Defines the shape of a subshell (e.g. spherical)

Question 3

Quantum number l can take values __________.

Answer 3

from 0 to n – 1

Question 4

When l = 0, the subshell is marked with the letter __.

Answer 4

s

Question 5

When l = 1, the subshell is marked with the letter __.

Answer 5

p

Question 6

When l = 2, the subshell is marked with the letter __.

Answer 6

d

Question 7

When l = 3, the subshell is marked with the letter __.

Answer 7

f

Question 8

Subshells are further split into energy levels known as orbitals.

What is an orbital?

Answer 8

An orbital describes where an e⁻ is likely to be found around a nucleus.

Question 9

Each orbital can hold a maximum of _____ e⁻.

Answer 9

two

Question 10

Shape of s orbital

Answer 10

Spherical

Question 11

Shape of p orbital

Answer 11

Dumbbell/8

Question 12

Shape of d orbital

Answer 12

Two intersecting p orbitals

Question 13

Arrange the subshells in order of increasing energy:

d, s, f, p

Answer 13

s, p, d, f

Question 14

In an isolated atom, all orbitals in a subshell are degenerate. This means they are ___________.

Answer 14

of equal energy

Question 15

Magnetic quantum number, m_ℓ

Answer 15

Defines orbital orientation in space (e.g. along y axis, or xy plane)

Question 16

m_ℓ can have values __________.

Answer 16

from −ℓ to +ℓ

(e.g. if ℓ = 1, m_ℓ = −1, 0, +1)

Question 17

Number of s orbitals in an s subshell

Answer 17

1

(1 orientation possible for a sphere)

Question 18

Number of p orbitals in a p subshell

Answer 18

3

(along x, y and z axes)

Question 19

Number of d orbitals in a d subshell

Answer 19

5

Question 20

Spin magnetic quantum number, m_s

Answer 20

Describes electron spin (+1/2 or –1/2)

Question 21

Aufbau principle

Answer 21

Electrons fill orbitals in order of increasing energy.

E.g. 1s before 2s, 2s before 2p.

Question 22

4s orbitals are an exception when filling orbitals because ___________.

Answer 22

they are filled before 3d.

Question 23

Hund’s rule

Answer 23

Electrons first fill degenerate orbitals singly with parallel spins.

Question 24

Pauli exclusion principle

Answer 24

No two e⁻ in one atom can have the same set of four quantum numbers.

(So no orbital can hold more than two e^{<strong>−</strong>} and these two e⁻ must have opposite spins.)

Question 25

Aluminium has the electronic configuration [Ne] 3s² 3p¹.

What does [Ne] mean?

Answer 25

Shorthand for electronic configuration of neon: 2, 8.

Question 26

Ground state

Answer 26

Lowest energy electronic configuration (default)

Question 27

Name the principle described

Electrons fill orbitals in order of increasing energy.

E.g. 1s before 2s, 2s before 2p.

Answer 27

Aufbau principle

Question 28

Name the principle described

Electrons first fill degenerate orbitals singly with parallel spins.

Answer 28

Hund’s rule

Question 29

Lowest energy electronic configuration (default)

Answer 29

Ground state

Question 30

Name the principle described

No two e⁻ in one atom can have the same set of four quantum numbers.

(So no orbital can hold more than two e^{<strong>−</strong>} and these two e⁻ must have opposite spins.)

Answer 30

Pauli exclusion principle

Question 31

What decides which block (s, p, d, f) in the periodic table an element is placed in?

Answer 31

Last occupied subshell

(e.g. 1s² 2s² 2p⁶ = p block)

Question 32

The s block contains __________.

Answer 32

groups 1 and 2, and helium

Question 33

The p block contains ___________.

Answer 33

groups 3 – 8, except helium

Question 34

The d block contains __________.

Answer 34

the transition metals

Question 35

The f block contains __________.

Answer 35

lanthanides and actinides

(subset of transition metals shown under the periodic table)

Question 36

The more stable the electronic configuration, the _____________ the ionisation energy.

Answer 36

higher

Question 37

State three features that make an electronic confiuguration stable.

Answer 37

Ends in a full shell (e.g. 2nd shell)

or full subshell (e.g. 3p⁶)

or half-filled subshell (e.g. 2p^₃).

Question 38

The more stable the electronic configuration, the ____ reactive the species.

Answer 38

less

Question 39

Bonding electron pairs

Answer 39

Electron pairs involved in covalent bonds

Question 40

Non-bonding (lone) electron pairs

Answer 40

Electron pairs not involved in covalent bonds

Question 41

Dative bond

Answer 41

A type of covalent bond formed when both bonding e⁻ are donated by one atom.

(The other atom accepts them into an empty orbital.)

Question 42

Electron pairs are negatively charged and ___________ each other. They are arranged in 3D to minimise repulsion and maximise separation.

Answer 42

repel

Question 43

Electron pairs are negatively charged and repel each other. They are arranged in 3D to minimise ____________ and maximise separation.

Answer 43

repulsion

Question 44

Electron pairs are negatively charged and repel each other. They are arranged in 3D to minimise repulsion and maximise _____________.

Answer 44

separation

Question 45

Name this type of bond

A type of covalent bond formed when both bonding e⁻ are donated by one atom.

(The other atom accepts them into an empty orbital.)

Answer 45

Dative bond

Question 46

To use VSEPR, it is necessary to find out the no. of e⁻ pairs surrounding a central atom.

To do this:

• ___________________________________________
• Add an e⁻ for every negative charge

•Remove an e⁻ for every positive charge

•Divide the total no. of e⁻ by two to give the number of e⁻ pairs.

Answer 46

Take the total number of valence e⁻ on the central atom and add one for each atom attached

Question 47

To use VSEPR, it is necessary to find out the no. of e⁻ pairs surrounding a central atom.

To do this:

• Take the total number of valence e⁻ on the central atom and add one for each atom attached
• _________________________________

•Remove an e⁻ for every positive charge

•Divide the total no. of e⁻ by two to give the number of e⁻ pairs.

Answer 47

Add an e⁻ for every negative charge

Question 48

To use VSEPR, it is necessary to find out the no. of e⁻ pairs surrounding a central atom.

To do this:

• Take the total number of valence e⁻ on the central atom and add one for each atom attached
• Add an e⁻ for every negative charge

•__________________________________

•Divide the total no. of e⁻ by two to give the number of e⁻ pairs.

Answer 48

Remove an e⁻ for every positive charge

Question 49

To use VSEPR, it is necessary to find out the no. of e⁻ pairs surrounding a central atom.

To do this:

• Take the total number of valence e⁻ on the central atom and add one for each atom attached
• Add an e⁻ for every negative charge

•Remove an e⁻ for every positive charge

•___________________________________

Answer 49

Divide the total no. of e⁻ by two to give the number of e⁻ pairs.

Question 50

Name this shape

Answer 50

Tetrahedral

Question 51

Name this shape

Answer 51

Trigonal bipyramidal

Question 52

Name this shape

Answer 52

Octahedral

Question 53

Name this shape

Answer 53

Trigonal planar

Question 54

Which combination of bonding and non-bonding electron pairs has the lowest repulsion?

Answer 54

Bonding + bonding

(repulsion reduced due to attraction to positive nuclei)

Question 55

Which combination of bonding and non-bonding electron pairs has the highest repulsion?

Answer 55

Non-bonding + non-bonding

Question 56

Shape when 6 bonding pairs are present

Answer 56

Octahedral

Question 57

Shape when 4 bonding pairs are present

Answer 57

Tetrahedral

Question 58

Shape when 3 bonding, 1 non-bonding pair are present

Answer 58

Trigonal pyramidal

Question 59

Shape when 2 bonding, 2 non-bonding pairs are present

Answer 59

Angular (e.g. H₂O)

Question 60

Shape when 5 bonding pairs are present

Answer 60

Trigonal bipyramidal

Question 61

Shape when 3 bonding pairs are present

Answer 61

Trigonal planar