C3 Structure And Bonding

Question 1

Particles in a solid

Answer 1

No gaps, tightly packed
Cannot be compressed
Vibrate about a fixed point
Regular arrangement
Particles all the same size
Strong forces holding them together

Question 2

Particles in a liquid

Answer 2

Particles are free to move - weak forces hold them together
Tightly packed, all touching and no spaces
No overlapping
Random arrangement
Cannot be compressed

Question 3

Particles in a gas

Answer 3

Spread out (none touching)
Particles all the same size
No overlapping
Random arrangement
Most energy required to break bonds

Question 4

Specific latent heat

Answer 4

Energy used to break bonds

Question 5

Steps in latent heat of fusion

Answer 5

1. Energy increases vibration of particles
2. Energy used to break bonds between solid particles.
3. Energy increases kinetic energy of liquid particles. Temperature increases, particles are faster. (LIQUID)
4. Energy used to overcome forces of attraction between particles.
5. Energy used increases random rapid movement of particles. (GAS)

Question 6

What is ionic bonding?

Answer 6

Oppositely charged ions are bonded between non-metals and metals.

Question 7

What is covalent bonding?

Answer 7

Atoms which share pairs of electrons. Mostly between non-metallic elements.

Question 8

What is metallic bonding?

Answer 8

Atoms which share delocalised electrons - in metallic elements and alloys.

Question 9

What are ions?

Answer 9

Atoms have a neutral charge because they always have an equal number of protons and electrons. If they gain/lose electrons, they become charge and are called ions.
Positive and negative ions stick together as opposite charges attract.
Atoms want to gain/lose electrons to achieve a full outer shell.
Metal atoms lose electrons- positive ions
Non-metal atoms gain electrons - negative ions.

Question 10

What is a period on the periodic table?

Answer 10

The number of electron shells of that element.

Question 11

What is a group on the periodic table?

Answer 11

Number of electrons in outer shell

Question 12

Maximum number of electrons in each shell?

Answer 12

2,8,8

Question 13

What is the overall charge of an ionic compound?

Answer 13

Balanced

Question 14

EXAMPLE QUESTION: Magnesium and dilute hydrochloride acid react to produce magnesium chloride solution and hydrogen. Explain why magnesium chloride has a formula MgCl2 and not MgCl

Answer 14

Because you need two chlorine atoms to bind to one magnesium atom to balance the overall charges.

Question 15

Properties of giant ionic structures

Answer 15

Ionic substances form giant lattices
Many strong electrostatic forces between the ions
Regular arrangement means they form crystals
Solid ionic substances do not conduct electricity as the ions are not free to move throughout the substance
High melting point
All solid at room temperature because the melting point is above room temp
Higher BP
Molten ionic substances can conduct electricity because molten ions are now free to move
Dissolved ionic substances can conduct electricity because dissolved ions are free to move

Question 16

Properties of ionic bonding

Answer 16

High MP and BP
Many strong electrostatic forces between ions
Lots of energy needed to separate ions

Question 17

Properties of covalent bonding

Answer 17

Weak intermolecular forces between molecules
Low MP/ BP
Not much energy needed to separate the molecules

Question 18

How is a double covalent bond written?

Answer 18

O = O

Question 19

Properties of small covalent molecules

Answer 19

Mostly gases at room temperature - low MP and BP (could be liquids too)
Weak intermolecular forces
BP below room temperature
Don’t require lots of energy to break

Question 20

What are giant covalent structures?

Answer 20

Some covalent structures form giant covalent structures where many atoms are held together in a regular arrangement
These are sometimes called macromolecules
Diamond and silicone dioxide
Graphite
Fullerenes

Question 21

Properties of diamond

Answer 21

Giant covalent structure
Very hard
High MP and BP due to 4 covalent bonds
Insoluble
Does not conduct electricity - no free electrons

Question 22

Properties of graphite

Answer 22

Bits rub off easily as layers can slide past each other due to weak hydrogen bond between solid layers
Can conduct electricity as only 3 covalent bonds, there are delocalised electrons (most giant covalent structures cannot)
Weak intermolecular forces

Question 23

Properties of Fullerenes

Answer 23

Could both be used as a lubricant
High tensile strength due to covalent bonds
High thermal and electrical conductivity
- 3 covalent bonds
Tiny in size (nano particles) - could be used for drug delivery within the body

Question 24

Properties of Buckminster Fullerene C60

Answer 24

Carbon atoms form hollow spheres
Could cage other molecules e.g. to deliver a drug
Huge SA so good as a catalyst

Question 25

Properties of a nanotube Cn

Answer 25

High tensile strength so good as a strengthening material High electrical conductivity so good for nano electronics Carbon atoms form hollow cylinders

Question 26

Properties of metals

Answer 26

Atoms of metals build later upon layer They form a regular arrangement Therefore they form crystals Not always visible to the naked eye Metals are a lattice of positively charged ions Outer electrons free to move about the structure - sea of delocalised electrons Malleable Strong electrostatic attraction between negatively charged electrons and positively charged ions bond the metal ions together Metals are good electrical and thermal conductors due to delocalised electrons Ductile Shiny until they react with oxygen

Question 27

Properties of iron

Answer 27

Pure metal particles form giant metallic structures Particle arranged closely packed layers in a regular arrangement meaning they can slide over each other

Question 28

Properties of metal alloys

Answer 28

Regular pattern disrupted Mixture Layers harder to slide over each other so it is harder Always generally harder than metals that make them up

Question 29

Structure of simple molecules

Answer 29

Substances made up of simple molecules have low melting points and boiling points. • The forces between simple molecules are weak. These weak intermolecular forces explain why substances made of simple molecules have low melting points and boiling points. • Simple molecules have no overall charge, so they cannot carry electrical charge. Therefore, substances made of simple molecules do not conduct electricity. • Models are used to help understand bonding but each model has its limitations in representing reality.