Chapter 5

Question 1

What is an electron shell?

Answer 1

• A group of atomic orbitals with the same principal quantum number (n)
• It is also called an energy level

Question 2

What is an orbital?

Answer 2

• A region around the nucleus that can hold up to 2 electrons with opposite spins

Question 3

List 4 types of orbitals.

Answer 3

• s
• p
• d
• f

Question 4

Describe s-orbitals.

Answer 4

• They are the shape of a sphere
• Every shell has 1 s-orbital

Question 5

Describe p-orbitals.

Answer 5

• They are the shape of a dumb-bell
• Each shell from n=2 and onwards contains 3 p-orbitals

Question 6

How many d-orbitals are there in each shell?

Answer 6

• From n=3 and onwards, there are 5 d-orbitals in each shell

Question 7

How many f-orbitals are in each shell?

Answer 7

• Each shell from n=4 and onwards contains 7 f-orbitals

Question 8

What is a sub-shell?

Answer 8

• A group of orbitals of the same type within a shell

Question 9

How do sub-shells in the same shell compare in terms of energy?

Answer 9

• Each new sub-shell added has more energy than the previous one

Question 10

How do the relative energy levels of the sub-shells of different shells compare?

Answer 10

• The sub-shells making up the first 4 shells generally stay in order from the s-orbital in n=1 having the least energy, and so on
• However, the 3d sub-shell is at a higher energy level than the 4s sub-shell

Question 11

How does the amount of energy each sub-shell has affect the order sub-shells are filled in?

Answer 11

• Sub-shells are filled in in order of ascending energy (so 1s first, and so on)
• 4s is at a lower energy level than 3d, so it it is filled first

Question 12

What do electrons-in-box models show?

Answer 12

• Electrons are represented by arrows that the either face up or down, which indicate its spin
• The 2 electrons in the same box must have opposite spins

Question 13

Why do 2 electrons in the same orbital have opposite spins?

Answer 13

• This helps to counteract their repulsion

Question 14

How do orbitals fill, and why?

Answer 14

• All orbitals within a sub-shell have the same energy
• 1 electron therefore occupies each orbital before they start to pair up (also prevents repulsion between paired electrons)

Question 15

What order are sub-shells written in for electronic configuration?

Answer 15

• In order of shell order rather than filling order (so 3d is written before 4s)

Question 16

How does the shorthand notation for electronic figurations work?

Answer 16

• You put the name of the previous noble gas in square brackets
• You then write the rest of the electronic configuration (if it has the same configuration as a noble gas, use the noble gas before this)

Question 17

Which sub-shells are affected when atoms lose or gain electrons?

Answer 17

• The one with the most energy
• The 3d energy level falls below the 4s energy level when it is (even partially) filled
• The 4s energy level therefore loses electrons (as well as filling) before the 3d energy level

Question 18

How is the periodic table divided into blocks?

Answer 18

• The blocks correspond to the elements’ highest energy sub-shell

Question 19

What are the different blocks in the periodic table?

Answer 19

• s-block is groups 1 and 2
• p-block is groups 3 to 0
• d-block is the centre block of 10 groups

Question 20

What is ionic bonding? Required.

Answer 20

• The electrostatic attraction between positive and negative ions

Question 21

What is an ionic lattice? Required.

Answer 21

• A repeating pattern of oppositely charged ions

Question 22

Why do ionic bonds result in the creation of a giant ionic lattice?

Answer 22

• Each ion attracts oppositely charged ions in all directions

Question 23

Describe the melting and boiling points of ionic compounds, and explain why they are like this.

Answer 23

• They have high melting and boiling points
• This is because large amounts of energy are needed to overcome the strong electrostatic attraction between the ions

Question 24

How do melting and boiling points differ across ionic compounds, and why?

Answer 24

• The melting and boiling points of lattices made of ions with greater ionic charges are higher
• This is because the ions are more strongly attracted together

Question 25

What type of solvents do ionic compounds dissolve in, and how?

Answer 25

• Polar solvents
• Water molecules are polar and surround each ion and break down the lattice

Question 26

Why does the solubility of ionic compounds differ?

Answer 26

• If the compound is made of ions with large charges, the ionic attraction may be too strong for the water molecules to break

Question 27

Do ionic compounds conduct electricity? Explain why.

Answer 27

• When in the liquid state or dissolved in water
• This is because in the solid state ions are in a fixed position in the giant ionic lattice, so solid ionic compounds are non-conductors of electricity
• When they are either liquid or aqueous, the solid ionic lattice breaks down and the ions are mobile, so in the liquid or aqueous state, an ionic compound is a conductor of electricity

Question 28

What is a covalent bond? Required.

Answer 28

• The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms

Question 29

What is a dative covalent bond, and what can it also be known as? How is it shown in displayed formulae?

Answer 29

• A covalent bond where the shared pair of electrons is supplied by one of the bonding atoms only (these electrons were originally a lone pair)
• Coordinate bond
• An arrow goes from the atom giving the electrons to the one it’s sharing them with

Question 30

What is average bond enthalpy?

Answer 30

• A measurement of the strength of a covalent bond (the higher the value, the stronger the covalent bond)