1.2 Atomic orbitals, electronic configurations and the periodic table

Question 1

How can the discrete lines in atomic spectra be explained?

Answer 1

If electrons, like photons, also display the properties of both particles and waves

Question 2

How do electrons behave?

Answer 2

as standing (stationary) waves in an atom

Question 3

Describe standing waves in an atom

Answer 3

• They are waves that vibrate in time but do not move in space
• There are different sizes and shapes of standing waves possible around the nucleus, known as orbitals

Question 4

What is the maximum number of electrons that an orbital can hold?

Answer 4

2

Question 5

What are the different shapes of orbitals defined as?

Answer 5

s, p, d and f

Question 6

Describe energy of electrons in atoms

Answer 6

electrons have fixed amounts of energy called quanta

Question 7

What is the purpose of quantum numbers?

Answer 7

to describe any electron in an atom

Question 8

what are the 4 quantum numbers?

Answer 8

• Principle quantum number
• Angular momentum quantum number
• Magnetic quantum number
• Spin magnetic quantum number

Question 9

Describe the principle quantum number

Answer 9

• n
• Indicates the main energy level for an atom and is related to the size of the orbital

Question 10

Describe the angular momentum quantum number

Answer 10

• l
• Determines the shape of the subshell and can have values from 0->n-1

Question 11

Describe the magnetic quantum number

Answer 11

• ml
  -determines the orientation of the orbital and can have values between -l -> +l

Question 12

Describe the spin magnetic quantum number

Answer 12

-ms
-determines the direction of spin and can have values of +1/2 or -1/2

Question 13

What 3 principles are electrons arranged according to?

Answer 13

• aufbau principle
• Hund’s rule
• The Pauli exclusion principle

Question 14

What is the aufbau principle?

Answer 14

Electrons fill orbitals in order of increasing energy

Question 15

What is Hund’s rule?

Answer 15

when degenerative orbitals are available, electrons fill up singly, keeping their spins parallel before spin pairing starts

Question 16

What is the Pauli exclusion principle?

Answer 16

No two electrons in one atom can have the same set of four quantum numbers, therefore no orbital can hold more than two electrons and these two electrons must have opposite spins.

Question 17

What orbitals are degenerate?

Answer 17

the orbitals within each subshell

Question 18

What can orbital box notation show?

Answer 18

the relative energies corresponding to each orbital

Question 19

Where is the s block?

Answer 19

left

Question 20

where is the p block?

Answer 20

right

Question 21

where is the d block?

Answer 21

transition metals

Question 22

Where is the f block

Answer 22

bottom

Question 23

How can the variation in the first, second and subsequent ionisation energies with increasing atomic numbers be explained?

Answer 23

• relative stability of different subshell electron configurations.
• This provides evidence for these electronic configurations.

Question 24

How can anomalies in the trend of ionisation energies be explained?

Answer 24

by considering the electronic configurations

Question 25

Explain stability and ionisation energies

Answer 25

the more stable the electronic configuration, the higher the ionisation energy.

Question 26

What is the special stability associated with?

Answer 26

half-filled and full subshells

Question 27

What can VESPR be used for?

Answer 27

Can be used to predict the shapes of molecules and polyatomic ions

Question 28

How can the number of electron pairs surrounding a central atom be found by?

Answer 28

-total number of outer electrons on the central atom and adding one for each atom attached
-adding an electron for each negative charge
-removing an electron for each positive charge
-dividing total by two to give total number of electron pairs

Question 29

Explain electron arrangement in relation to each other

Answer 29

• e- pairs are negatively charged and repel each other
• they are arranged to minimise repulsion and maximise separation

Question 30

Atomic shape for 2 electron pairs?

Answer 30

linear

Question 31

Atomic shape for 3 electron pairs?

Answer 31

trigonal planar

Question 32

Atomic shape for 4 electron pairs?

Answer 32

tetrahedral

Question 33

Atomic shape for 5 electron pairs?

Answer 33

trigonal bipyramidal

Question 34

Atomic shape for 6 electron pairs?

Answer 34

Octahedral

Question 35

How are shapes of molecules or polyatomic ions determined?

Answer 35

-by the shapes adopted by the atoms present based on the arrangement of electron pairs.
-electron dot diagrams can be used to show these arrangements

Question 36

What is the order of electron pair repulsions in decreasing strength order?

Answer 36

non-bonding pair/non-bonding pair>non-bonding/bonding pair>bonding pair/bondjng pair