F321 - Electrons, Bonding and Structure

Question 0

What does the term successive ionisation energies mean?

Answer 0

The amount of energy required to remove a further electron from one mole of ions of an element in the gaseous state.

Question 1

What does the term first ionisation energy mean?

Answer 1

The amount of energy needed to remove one electron from each atom in one mole of atoms of an element in the gaseous state.

Question 2

What factors influence ionisation energy?

Answer 2

The size of the nuclear charge, the distance of the electron from the nucleus and the electron shielding from the filled inner shells.

Question 3

How does nuclear charge effect ionisation energy?

Answer 3

As nuclear charge increases (with increasing atomic number) ionisation energy increases as there is a greater attraction between the protons and electrons.

Question 4

How does the distance between the electron and nucleus effect ionisation energy?

Answer 4

As the distance increases the ionisation energy decreases as the force if attraction becomes less the further away the attracted bodies are from each other.

Question 5

How does the shielding from the inner shells of electrons effect ionisation energy?

Answer 5

The greater the shielding effect (the more filled shells between the nucleus and the outer electrons) the lower the ionisation energy as the negative electrons will repel each other and reduce the effect of the positive nuclear charge.

Question 6

How many electrons can fit into each of the first four shells?

Answer 6

First = 2
Second = 8
Third = 18
Fourth = 32

Question 7

What is an orbital?

Answer 7

A region/area that can hold up to two electrons with opposite spins.

Question 8

What is the shape of an s orbital?

Answer 8

Sphere

Question 9

What is the shape of a p orbital?

Answer 9

2 Lobes (along the x, y and z axes)

Question 10

What is the number of orbitals and electrons making up an s-sub shell?

Answer 10

One orbital and two electrons.

Question 11

What is the number of orbitals and electrons making up an p-sub shell?

Answer 11

Three orbitals and six electrons.

Question 12

What is the number of orbitals and electrons making up an d-sub shell?

Answer 12

5 orbitals and 10 electrons.

Question 13

How do electrons fill orbitals?

Answer 13

Electrons will occupy orbitals singly (due to repulsion of negative charges) until the available orbitals of equal energy have one electron each. This forces then to spin-pair in one orbital of that energy level.

Question 14

What is ionic bonding?

Answer 14

The electrostatic attraction between oppositely charged ions.

Question 15

What is covalent bonding?

Answer 15

The sharing of electrons (as a pair) to form a bond.

Question 16

What is a dative covalent bond?

Answer 16

A covalent bond where both electrons come from one atom.

Question 17

What determines the shape if simple molecules?

Answer 17

The repulsion between electron pairs surrounding the central atom.

Question 18

Which type of electrons causes the most repulsion?

Answer 18

Lone pairs of electrons cause more repulsion than bonding pairs.

Question 19

How many bonding and lone pairs of electrons are there in a molecule with a trigonal planar shape? What are the bond angles?

Answer 19

Bonding pairs: 3
Lone pairs: 0
Bond angle: 120

Question 20

How many bonding and lone pairs of electrons are there in a molecule with a tetrahedral shape? What are the bond angles?

Answer 20

Bonding: 4
Lone: 0
Bond angle: 109.5

Question 21

How many bonding and lone pairs of electrons are there in a molecule with an octahedral shape? What are the bond angles?

Answer 21

Bonding: 6
Lone: 0
Bond angle: 90

Question 22

How many bonding and lone pairs of electrons are there in a molecule with a pyramidal shape? What are the bond angles?

Answer 22

Bonding: 3
Lone: 1
Bond angle: 107

Question 23

How many bonding and lone pairs of electrons are there in a molecule with a non-linear shape? What are the bond angles?

Answer 23

Bonding: 2
Lone: 2
Bond angle: 104.5

Question 24

How many bonding and lone pairs of electrons are there in a molecule with a linear shape? What are the bond angles?

Answer 24

Bonding: 2-4
Lone: 0
Bond angle: 180

Question 25

What is electronegativity?

Answer 25

The ability of an atom to attract the bonding electrons in a covalent bond.

Question 26

What causes a polar covalent bond?

Answer 26

Two bonding electrons are not shared equally by the two bonded atoms. The atom with the bigger share of the two electrons becomes slightly negative while the other becomes slightly positive based on then having different electronegativities.

Question 27

What are intramolecular bonds?

Answer 27

The bonds within a compound.

Question 28

What are intermolecular bonds?

Answer 28

Forces of attraction between molecules.

Question 29

When do permanent dipole-dipole forces arise?

Answer 29

When a molecule is polar and interacts with another polar molecule.

Question 30

When do induced/instantaneous dipole forces (van der Waals’) arise?

Answer 30

The forces arise because electrons in atoms or molecules can be thought of as lying to one side of the atom or molecule than the other. The imbalance provides a slight negative and positive charge to arise causing a weak attraction between the molecules.

Question 31

What is a hydrogen bond?

Answer 31

A weak intermolecular bond formed between molecules containing a hydrogen atom bonded to one of the most electronegative elements (N, O or F).

Question 32

List the intermolecular forces in order of strength from weakest to strongest.

Answer 32

van der Waals’
dipole-dipole
Hydrogen bonding

Question 33

Why does water have a higher than expected boiling point?

Answer 33

When water goes from the liquid to gaseous state the stronger hydrogen bonds between molecules need to be broken.

Question 34

Why is the freezing point of water higher than predicted?

Answer 34

Ice forms a three dimensional hydrogen bonded lattice which raises the freezing point she to the large number of hydrogen bonds between water molecules.

Question 35

What is metallic bonding?

Answer 35

The attraction between positive metal ions and the delocalised electrons within a metal structure.