Module 2 Chapter 5

Question 1

Number of electrons that can fill shells?

Answer 1

2n^2

Question 2

Define atomic orbitals

Answer 2

A region around the nucleus that can hold up to two electrons with different spins

Question 3

Shape of s-orbital

Answer 3

Sphere

Question 4

Shape of p-orbital

Answer 4

Dumb-bell shape

Question 5

Number of orbitals in sub-shells?

Answer 5

s=1
p=3
d=5

Question 6

Number of electrons in sub shells?

Answer 6

double no. orbitals
s=2
p=6
d=10

Question 7

How do electrons fill orbitals?

Answer 7

• Lowest energy first (Aufbau Principle)
• With opposite spins in each orbital (Pauli Exclusion Principle)
• Not doubling up until they have to - ‘antisocial people on the bus’ rule (Hund’s Rule)

Question 8

Define ionic bonding

Answer 8

The electrostatic attraction between oppositely charged ions in all directions

Question 9

What are blocks named after in the periodic table?

Answer 9

The highest energy subshell filled (containing electrons) in the elements in them

Question 10

Define covalent bond

Answer 10

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

Question 11

Define ‘giant ionic lattice’

Answer 11

A repeating pattern of oppositely charged ions fixed in position. They contain no intermolecular forces

Question 12

What is the trend in melting/boiling points of ionic compounds?

Answer 12

• high mp/bp
  • high energy/temperatures required to overcome electrostatic attractive forces
• Strength of the ionic bond increases when:
  • charge on ions increased
  • size of ions decreased

Question 13

What are ionic compounds soluble in?

Answer 13

• polar solvents (H2O) which break down the lattice and surround each ion
• polar molecules attracted towards ions on surface
• bond to ions
• ionic bonds broken; ions surrounded
• hydration releases energy to compensate for energy needed to break ionic bonds

Question 14

Can ionic compounds conduct electricity?

Answer 14

Not in solid state, but can when liquid or aqueous.
- ions are free to move
- ions are mobile charge carriers
- electricity is conducted

Question 15

Define lone pairs

Answer 15

A pair of electrons not involved in bonding

Question 16

Define a dative bond

Answer 16

A covalent bond in which both bonding electrons come from the same atom

Question 17

Exceptions to the octet rule?

Answer 17

• BF3: there 6 electrons around the B atom, which is ‘electron deficient’
• Expansion of the octet in molecules containing atoms with the d subshell available (e.g. Si, P, S)