Section 10

Question 1

The atom

Answer 1

Nucleus – contains protons and neutrons
Protons = relative mass = 1, relative charge +1
Electron = relative mass = 1/1837, relative charge = -1
Neutron = relative mass = 1, relative charge = 0

Question 2

Isotopes and relative atomic mass

Answer 2

Isotopes – same number of protons different number of neutrons
Relative atomic mass is worked out from isotope abundance is – multiply each mass by isotopic abundancies and add up results and divide sum by abundances

Question 3

Electronic configuration

Answer 3

Number of shells – shows period

Group number – shown by amounts of electrons in outershell

Question 4

Ions

Answer 4

They are charged particles negative ions (anions) form when atoms gain electrons
Positive ions (cat ions) form when atom loses electrons
Groups 1, 2, 6, 7 are most likely to form ions

Question 5

Ionic bonding

Answer 5

Is the transfer of electrons

Use dot and cross diagrams

Question 6

Ionic compounds

Answer 6

Hi melting and boiling points due to strong attraction so takes lots of energy to break
Regular lattice structure
Don’t conduct electricity

Question 7

Ionic compound models

Answer 7

2d representations - show the atoms and how they’re connected don’t show shape or size

Dot and cross diagrams- show how compounds/molecules are formed don’t show size or arrangement

3D models - show arrangement but only show outer layer

Question 8

Convalent bonding

Answer 8

Simple molecular structures
Held together by very strong covalent bonds.
Forces of attraction are weak
Melting and boiling points low but increase as size increases
Don’t conduct electricity

Question 9

Giant covalent structures and fullerenes

Answer 9

Bonded by strong covalent bonds
High melting and boiling points
Don’t conduct electricity
Aren’t soluble
Diamond- carbon atoms each form 4 covalent bonds
Graphite- each carbon atom forms 3 covalent bonds
Fullerenes are molecules of carbon

Question 10

Metallic bonding

Answer 10

High melting and boiling points
Conduct electricity
Arent soluble
Involves Delocalised electrons
Strong forces of electrostatic attraction – needs lots of energy to be broken

Question 11

Conservation of mass

Answer 11

The chemical reaction mass is always conserved
During a chemical reaction no atoms are destroyed and no atoms are created
Good way of showing this is to do a precipitation reaction

Question 12

Relative mass and empirical formula

Answer 12

Find relative atomic mass of each atom and add it together = relative mass
M, F, A, S = maths, formula mass, atomic mass, symbol equation

Question 13

Moles

Answer 13

Moles = mass ÷ relative atomic mass
One mole of atoms or molecules of any substance will have a mass in grams equal to the relative atomic mass for that substance

Question 14

Concentration

Answer 14

Concentration = mass solute ÷ volume of solution

The more solute you dissolve in a given volume the more crowded the particles so the more concentrated

Question 15

Limiting reactants

Answer 15

Reactions stop when one reactant is used up

The amount of product formed is directly proportional to the amount of limiting reactant