Topic 1

Question 1

What are ions?

Answer 1

Ions are charged particles that can be single atoms or groups of atoms.

Question 2

Why do atoms form ions?

Answer 2

To gain a full outer shell.

Question 3

What happens when an atom gains electrons?

Answer 3

It forms negative ions (anions)

Question 4

What happens when an atom loses electrons?

Answer 4

It forms positive ions (cations)

Question 5

What are group 1 and 2 elements and what are their charges?

Answer 5

They are metals
Group 1 forms 1+ ions
Group 2 forms 2+ ions

Question 6

What are group 6 and 7 elements and what are their charges?

Answer 6

They are non-metals
Group 6 forms 2- ions
Group 7 forms 1- ions

Question 7

What do these elements have in common?

Answer 7

They form ions most readily

Question 8

What is an ionic bond?

Answer 8

When a metal and a non-metal transfer electrons so the metal loses atoms (cation) and the non-metal gains electrons (anion) to gain a full outer shell. They are strongly attracted to each other by electrostatic forces.

Question 9

What structures do ionic compounds have?

Answer 9

Giant ionic lattice structures with very strong electrostatic forces of attraction between oppositely charged ions.

Question 10

Why do ionic compounds have high melting and boiling points?

Answer 10

Due to the strong attraction between the ions, it takes a large amount of energy to overcome it.

Question 11

Why don’t solid ionic compounds conduct electricity?

Answer 11

The ions are fixed in place and can’t move. However when they melt, the ions are free to move and will carry an electric current.

Some also dissolve in water easily.

Question 12

What are the advantages and disadvantages of 2D representations of structures?

Answer 12

They are simple and good at showing what atoms something contains and how the atoms are connected but don’t show the shape of the substances or the size of the atoms.

Question 13

What are the advantages and disadvantages of dot and cross diagrams?

Answer 13

Useful for showing how compounds and molecules are formed and where the electrons in bonds/ions come from but don’t show size of atoms/ions or arrangement.

Question 14

What are the advantages and disadvantages of 3D models of ionic solids?

Answer 14

Show arrangement of ions but only show outer layer of substance.

Question 15

What are the advantages and disadvantages of ball and stick models?

Answer 15

They’re good helping visualise structures
They’re more realistic than 2D drawings
Though they have big gaps between the atoms but in reality this where the electron clouds interact.
They don’t show correct scales of ions or atoms

Question 16

What is a covalent bond?

Answer 16

A strong bond that forms when a pair of electrons is shared between 2 atoms

Question 17

What are some examples of molecules with atoms joined by covalent bonds?

Answer 17

H2
H20
HCL
CH4
CO2
O2

Question 18

What structures do substances containing covalent bonds usually have?

Answer 18

Simple molecular structures

Question 19

Why do simple molecular structures have low melting and boiling points?

Answer 19

The atoms in the molecules are held together by very strong covalent bonds but the forces off attractive between the MOLECULES are very weak so little energy is needed to break these intermolecular forces.`

Question 20

What state are most molecular substances at room temperature?

Answer 20

Liquids and gases

Question 21

What happens as the molecules get bigger?

Answer 21

The strength of the intermolecular forces increase, so more energy is needed to break them so the melting and boiling point increase.

Question 22

Why don’t molecular compounds conduct electricity?

Answer 22

They don’t contain any free moving ions/electrons

Question 23

What are the 4 properties of most giant covalent structures?

Answer 23

• All the atoms are bonded together by strong covalent bonds
• They have very high melting and boiling points so lots of energy is needed to break the bonds
• they generally don’t have charged particles so don’t conduct electricity
• they aren’t soluble in water

Question 24

Give 4 properties of Diamond

Answer 24

• its made up of a network of carbon atoms that each form 4 covalent bonds
• The strong covalent bonds take lots of energy to break so diamond has a high melting point
• the strong covalent bonds hold the atoms in a rigid lattice structure making them really hard
• they can be used to sharpen/strengthen cutting tools
• it doesn’t conduct electricity because it has no free electrons/ions

Question 25

What is a metallic bond?

Answer 25

The electrons in the outer shell of metal atoms are delocalised which produce all of the properties

There are strong forces of electrostatic attraction between the positive metal ions and the shared negative electrons.

the forces of attraction hold the atoms together in a regular structure and are known as metallic bonding which very strong

Question 26

What is the formula for moles?

Answer 26

Moles= mass x Mr

Question 27

What is the formula for concentration?

Answer 27

Concentration= mass of solute/ volume of solute