Structure and Bonding

Question 1

Ionic compounds

Answer 1

Ions form by electron transfer between metals (+) and non-metals (-)
The ions are oppositely charged
E.g Magnesium + oxygen -> magnesium oxide
(Cross and dot diagram)

Question 2

Ionic bond

• what is it?
• what does it produce?
• how is it formed?

Answer 2

-An ionic bond is a strong electrostatic force of attraction between 2 oppositely charged ions
-Ionic bonds always produce giant ionic structures
Forms by:
1. Electron transfer
2. Formation of ions
3. Electrostatic attraction
4. Formation of lattice

Question 3

Properties of ionic compounds

Answer 3

-High melting and boiling points (strong electrostatic force, lots of energy required to break)
-Doesnt conduct electricity when solid (ions are not free to move)
-Conducts when dissolved or molten (ions free to move, pass charges)
-Soluble in water
-Bigger* the charges the stronger the bonds because there’s a strong electrostatic force
Note: Noble gases are unreactive because their atoms have *stable electronic arrangements + full outer shells

Question 4

Ionic crystal

Answer 4

A giant 3 dimensional lattice held together by the attraction between oppositely charged ions

Question 5

OIL RIG

Answer 5

Oxidation
Is
Loss of electrons

Reduction
Is
Gain of electrons

Question 6

Covalent bonding

Answer 6

A strong attraction between the bonding pair of electrons and the nuclei of the atoms

Question 7

Formation of a covalent bond

Answer 7

The sharing of a pair of electrons between atoms so that both atoms achieve a full outer shell.
Mainly occurs between non-metals

Question 8

Properties of a giant covalent lattice

Answer 8

• very high boiling and melting points (strong covalent bonds,lots of energy required to break)
• doesnt conduct electricity (except graphite) when solid, dissolved or molten(no delocalised electrons)
• insoluble in water

Question 9

Graphite

Answer 9

• weak forces of attraction between layers so layers slide over each other
• delocalised electrons can carry charges and conduct electricity
• used as electrodes, lubricant and pencil lead

Question 10

Diamond

Answer 10

• hardest material known
• 4 strong covalent bonds
• used as cutting tools and drills

Question 11

Draw the lattice of doom

Answer 11

Do it

Question 12

Draw the position of atoms in diamonds and graphite

Answer 12

Just do it

Question 13

Simple molecular structures

Answer 13

• tends to be gases, liquids or solids
• low melting/boiling point due to weak intermolecular forces that break easily
• non-metal
• doesn’t conduct electricity because no delocalised electrons or overall charge
• tends to be insoluble

Question 14

Dots and cross diagrams for covalent compounds:

• hydrogen
• chlorine
• hydrogen chloride
• water
• methane
• ammonia
• oxygen
• nitrogen
• carbon dioxide
• ethane
• ethane

Answer 14

Do it

Question 15

Metallic crystals

Answer 15

• giant structure of positive ions surrounded by a sea of delocalised electrons
• high melting/boiling point due to strong electrostatic forces that hold together ions and electrons
• conducts electricity because delocalised electrons are free to move and pass charges
• malleable (bent) and ductile (stretched) because layers of atoms are able to move over each other
• insoluble

Question 16

How do you deduce the charge of an ion?

Answer 16

In group 1 , 2, 3: lose electrons

In group 6, 7: gain electrons