Module 2

Question 1

What term is given to the ‘•x H2O’ part of the formula? (1)

Answer 1

Water of Crystallization

Question 2

Explain what is meant by the term salt. (1)

Answer 2

when the H+ in an acid is replaced by a metal ion OR an ammonium ion OR a + ion

Question 3

Suggest how magnesium oxide becomes contaminated with magnesium carbonate (1)

Answer 3

MgO reacts with CO2

Question 4

State one important use for the compound (NH4)2SO4 (1)

Answer 4

Fertilizer

Question 5

Define the term relative isotopic mass. (2)

Answer 5

Mass of atom/isotope compared to 1/12th of a carbon-12 atom.

Question 6

Determine why “X” has a lower first IE than “Y”. (Where “Y” is further down group than “X”) (3)

Answer 6

Xe has a bigger atomic radius OR Xe has more shells (1) /// Xe has more shielding (2) /// The nuclear attraction decreases OR Outermost electrons of Xe experience less attraction (to nucleus) OR Increased shielding / distance outweighs the increased nuclear charge (3)

Question 7

What are the Bond Angles in a tetrahedral shaped molecule? (3)

Answer 7

109.5

Question 8

When ionic salt “X” is solid it doesn’t conduct but when it is dissolved in water/molten it does conduct. Explain. (2)

Answer 8

Ions can’t move in solid (ionic lattice) (1)/// Ions can move/are mobile in molten/aqueous/in solution. (2)

Question 9

Define first ionization energy (3)

Answer 9

The energy required to remove one electron (1)//from each atom in one mole (2)//of gaseous atoms. (3)

Question 10

Suggest why the second ionization energy of oxygen has a greater value than the first ionization energy of oxygen. (1)

Answer 10

the O+ ion, is smaller than the O atom OR the electron repulsion/shielding is smaller OR the proton: electron ratio in the 2+ ion is greater than in the 1+ ion.

Question 11

Explain how the information in the table above provides evidence for two electron shells in oxygen. (Table includes large jump in ionization energy from 6-7) (2)

Answer 11

Large difference between 6th and 7th IEs (1)//Marks a different shell (2)

Question 12

Describe and explain the trend in first ionization energies shown by the Period 2 elements, Li–N. (6)

Answer 12

From Li → N, ionization energy increases (1)/// number of protons/nuclear charge increases (2)// meaning nuclear attraction increases / shell drawn in by increased nuclear charge/ atomic radius decreases across period (3) /// From Be → B, ionization energy decreases (4)/// for B, electron is removed from a p sub-shell/p orbital/different sub-shell (5)// which has higher energy meaning electron is removed easier (6).

Question 13

Why does adding more Calcium still cause a reaction in a solution in which calcium and HCL previously reacted exactly. (use equation) (2)

Answer 13

Calcium reacts with the water produced in the original reaction between HCl and Ca, producing Ca(OH)2. (1)///Ca(s) + H2O(l) → Ca(OH)2 (aq) + H2 (g) (2)

Question 14

What is meant by the term “ionic bonding” (1)

Answer 14

Electrostatic attraction between oppositely charged ions

Question 15

Predict the bond angle in an F2O molecule. Explain your answer. (3)

Answer 15

Predicted bond angle 104 – 105°. (1) /// There are 2 bonded pairs and 2 lone pairs (2) // Lone pairs repel more than bonded pairs (3)

Question 16

Describe and explain one anomalous property of water which results from hydrogen bonding. (2)

Answer 16

Liquid H2O is denser than solid (1) //in solid state H2O molecules are held apart by hydrogen bonds (2)/// H2O has a relatively high boiling point OR melting point (1)// (relatively strong) hydrogen bonds need to be broken (2)

Question 17

Describe the difference in structure and bonding between Chlorine and magnesium. Explain the difference in melting point. (6)

Answer 17

Mg has a giant structure (1)// Mg has metallic bonding OR description of metallic bonding as positive ions and delocalized electrons (2)//(There is electrostatic attraction between) positive ions and electrons (3)//Cl has a simple molecular OR simple covalent (lattice) (4)//Cl has van der Waals’ forces (between molecules) OR Cl has instantaneous dipole–induced dipoles OR temporary dipole–temporary dipole (5)// Less energy is needed to overcome van der Waals’ than metallic bonds (6)

Question 18

Explain what is meant by a covalent bond (1)

Answer 18

A shared pair of electrons

Question 19

Describe the bonding and structure in graphite. Hence explain why graphite is soft and has a high melting point (5)

Answer 19

ghiant covalent (lattice) (1) // layers with intermolecular bonds between them (2)/// high melting / boiling point – because strong OR covalent bonds have to be broken (3)// layers can slide over each other

Question 20

Name the shape of an ammonia molecule and explain why its bond angles are 107 (3)

Answer 20

Shape: pyramidal OR (trigonal) pyramid (1)///Explanation: There are 3 bonded pairs and 1 lone pair// Lone pairs repel more than bonded pairs (lone pairs decrease bond angle by 2.5)(2)(3)

Question 21

suggest why H2S has a much lower boiling point than H2O. (1)

Answer 21

Weaker intermolecular force due to no hydrogen bonding

Question 22

Explain, with a diagram, what is meant by hydrogen bonding

Answer 22

H bonding from lone pair on O of 1 H2O molecule to H of another (1)

Question 23

Explain the term electronegativity.

Answer 23

Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons.

Question 24

Explain why silicon has a much higher boiling point than phosphorus. (2)

Answer 24

Si has strong forces between atoms/ covalent bonds are broken (1) P has weak forces between molecules/ intermolecular forces/van der Waals’ forces are broken (2)

Question 25

Explain why the boiling point increases from sodium to aluminium. (2)

Answer 25

Charge on positive ion increases/ ionic size decreases/ charge density increases attraction between + ions and electrons increases/ metallic bonding gets stronger