Topic 2.1 ionic

Question 1

Ionic compounds are held together by strong electrostatic forces of attraction between oppositely charged ions. These forces act in all directions in the lattice and this is called __________.

Answer 1

Ionic compounds are held together by strong electrostatic forces of attraction between oppositely charged ions. These forces act in all directions in the lattice and this is called IONIC BONDING

Question 2

State the properties of ionic compounds

Answer 2

Ionic compounds have high melting points and high boiling points

Ionic compounds can conduct electricity when melted or dissolved in water

Question 3

Explain why ionic compounds have high melting and boiling points

Answer 3

Ionic compounds have high melting and boiling points because a lot of energy is needed to break the strong electrostatic forces of attraction between the positively and negatively charged ions

Question 4

Explain why ionic compounds cannot conduct electricity when solid

Answer 4

Ionic compounds cannot conduct electricity when they are solids.

This is because, the ions are fixed in position in a giant lattice. They vibrate but cannot move around and carry a charge.

Question 5

Explain why ionic compounds can conduct electricity when molten or dissolved in water

Answer 5

Ionic compounds can conduct electricity when they are melted or dissolved in water.

This is because the ions are free to move and can carry a charge.

Question 6

Explain why ionic compounds can conduct electricity when molten

Answer 6

Ionic compounds can conduct electricity when molten.

This is because the high temperature provides enough energy to overcome the many strong electrostatic forces between the oppositely charged ions. Ions are free to move around within the molten compound and can carry a charge

Question 7

Explain why ionic compounds can conduct electricity when dissolved in water

Answer 7

Ionic compounds can conduct electricity when dissolved in water.

This is because the water molecules separate the ions from the lattice. The ions are free to move around within the solution and can carry a charge.

Question 8

What happens when an ionic compound is dissolved in water

Answer 8

When an ionic compound is dissolved in water the lattice is split up by the water molecules (the lattice breaks down). The ions are then free to move around within the solution formed and can carry a charge

Question 9

What do ionic substances form

Answer 9

Ionic substances form giant ionic lattices containing oppositely charged ions

Question 10

What do giant ionic lattices contain

Answer 10

Giant ionic lattices contain oppositely charged ions

Question 11

What are the ways to increase the conductivity of an ionic substance

Answer 11

The ways to increase the conductivity of an ionic substance are:

Melt the ionic substance to make it molten
Dissolve the ionic substance in water

Question 12

Which of these ions will move to the positive electrode and which of these ions will move the negative electrode

lithium ions
chloride ions
bromide ions
calcium ions
zinc ions
sodium ions
oxide ions
barium ions
iodide ions

Answer 12

The ions that will move to the positive electrode

Chloride ions
Bromide ions
Oxide ions
Iodide ions
(These are the negative ions - opposite charges attract)

The ions that will move to the negative electrode

Lithium ions
Calcium ions
Zinc Ions
Sodium Ions
Barium Ions

(These are positive ions - opposite charges attract)

Question 13

State the ionic formula for:

Sodium Iodide
Potassium Oxide
Aluminium nitrate
Ammonium Astatide
Rubidium sulfate
Copper (II) oxide
Zinc (II) bromide

Answer 13

Sodium Iodide
NaI

Potassium Oxide
K2O

Aluminium nitrate
Al(NO3)3

Ammonium Astatide
NH4At

Rubidium sulfate
RbSO4

Copper (II) oxide
CuO

Zinc (II) bromide
ZnBr2

Question 14

State the charge for these ions

Nitrate
Carbonate
Sulfate
Hydroxide
Ammonium
Phosphate
Silver
Zinc

Answer 14

Nitrate
NO3-

Carbonate
CO3 2-

Sulfate
SO4 2-

Hydroxide
OH-

Ammonium
NH4+

Phosphate
PO4 3-

Silver
Ag 1+

Zinc
Zn 2+

Question 15

What is the formula for the following compounds

ammonia
ammonium

Answer 15

ammonia
NH3

ammonium
NH4

Question 16

Potassium forms an ionic compound with sulfur

Describe what happens when two atoms of potassium react with one atom of sulfur

Give your answer in terms of electron transfer

Answer 16

Electrons are transferred from the potassium atoms to the sulfur atom

Two potassium atoms react with 1 sulfur atom

The two potassium atoms each lose one electron

To form an ion with a charge of 1+ (forming Potassium ions (K+ / 1+ ions)

The Sulfur atom gains 2 electrons

To form an ion with a charge of 2- (forming sulfide ions (S2− / 2− ions)

This results in the potassium ion and the sulfide ions achieving a complete outer shell and attaining the electronic structure of a noble gas.

Question 17

Magnesium chloride contains magnesium ions (Mg 2+) and chloride ions (Cl -)

Describe in terms of electrons what happens when a magnesium atoms reacts with chlorine atoms to produce magnesium chloride

Answer 17

Electrons are transferred from the magnesium atom to the chlorine atoms

The magnesium atoms loses 2 electrons
to form an ion with a charge of 2+ (forming magnesium ions Mg 2+ ions)

2 chlorine atoms react with 1 magnesium atom
Each chlorine atom gains 1 electron
To form an ion with a charge of 1- ( forming chloride ions Cl- ions)

This results in the magnesium ion and the chloride ions achieving a complete outer shell and attaining the electronic structure of a noble gas.

Question 18

Describe the structure of a ionic compound

Answer 18

Ionic compounds have a giant ionic lattice structure

The ions form a closely packed regular lattice arrangement , held together by strong electrostatic forces of attraction between oppositely charged ions, in all directions in the lattice

Question 19

Magnesium oxide contains magnesium ions (Mg2+) and oxide ions (O2–)

Describe, as fully as you can, what happens when magnesium atoms react with oxygen atoms to produce magnesium oxide.

Answer 19

Electrons are transferred from the magnesium atom to the oxygen atom

The magnesium atoms loses 2 electrons
to form an ion with a charge of 2+ (forming magnesium ions Mg 2+ ions)

The oxygen atom gains 2 electrons
To form an ion with a charge of 2- ( forming oxide ions O2- ions)

This results in the magnesium ion and the oxide ion achieving a complete outer shell and attaining the electronic structure of a noble gas.

Question 20

Explain why metal atoms form positively charged ions whereas non-metal atoms form negatively charged ions

Answer 20

Metal atoms have fewer electrons in outer shell

so lose electrons to form ions

with stable electronic structure of noble gas

The metal ions contain more protons than electrons, giving positive ions.

*Non-metal atoms with 5, 6 or 7 electrons in outer shells
*gain electrons to form ions *with electronic structure of noble gas
*ions have more electrons than protons, resulting in negative ions

Question 21

In ionic bonding, the ___________ are transferred from the _______ to the ____________________

Answer 21

In ionic bonding, the outer electrons are transferred from the metal atom to the non-metal atom

Question 22

State the empirical formula for sodium chloride

Answer 22

NaCl - its just the ionic formula.
Empirical formula - a formula that is showing the simplest possible whole number ratio of atoms in a compound