Chapter 2

Question 1

Elements

Answer 1

Consits of one type of atom only

Question 2

Compunds

Answer 2

Made up of two or more different elements which are chemically bonded together -> properties of compound differ from properties of original elements + difficult to seperate

Question 3

Mixtures

Answer 3

Made up of two or more elements or compunds that aren’t chemically bonded together -> properties of mixture: a mixture of the properties of seperate parts + easily seperated with pysical methods

Question 4

Atomic structure

Answer 4

Central nucleus containing protons and neutrons surrounded by electrons in shells

Question 5

Neutral atoms

Answer 5

No overall charge as number of protons is equal to number of electrons -> if some electrons are added or removed the atom becomes charged and is now an ion

Question 6

Relative mass of proton

Answer 6

1

Question 7

Relative mass of neutron

Answer 7

1

Question 8

Relative mass of electron

Answer 8

Approx 0 -> 0.0005

Question 9

Relative charge of proton

Answer 9

+1

Question 10

Relative charge of neutron

Answer 10

0

Question 11

Relative charge of electron

Answer 11

-1

Question 12

Atomic number/ proton number

Answer 12

Number of protons in nucleus of atom -> in neutral atom this tells us the element
(Smaller number)

Question 13

Mass number/nucleon number

Answer 13

Number of protons and neutrons in nucleus of atom
(Bigger number)

Question 14

Isotopes

Answer 14

Different atoms of the same element that have the same number of protons but different number of neutrons
- Isotopes have the same chemical properties, as chemical properties depend on the number of electrons and isotopes have the same number of electrons/electronic configuration

Question 15

Relative atomic mass of an element (Ar)

Answer 15

Average mass of all isotopes of the element

Question 16

Electron shell rules

Answer 16

• Electrons always occupy shells (energy levels)
• Lowest shells always filled first -> shells closest to nucleus
• Certain capacity of electrons in each shell

Question 17

1st shell

Answer 17

2 electrons

Question 18

2nd and 3rd shell

Answer 18

8

Question 19

Outer shell electrons

Answer 19

Control reactivity as they from bonds with other atoms to gain or loose enough electrons to achieve a full outer shell and become stable + unreative

Question 20

Ions

Answer 20

Charged particles

Question 21

Anions

Answer 21

Negative ions -> form when atoms gain electroms

Question 22

Cations

Answer 22

Positive ions-> form when atoms loose electrons

Question 23

Ionic bonding

Answer 23

Between metals and non-metals -> metal atom looses electrons to form a cation and a nonmetal gains these electrons to form an anion
- These oppositely charged ions are strongly attracted to each other by electrostatic attractions -> ionic bonding

Question 24

Ionic compund properties

Answer 24

Always have gaint ionic structure -> regular arrangement of alternating positive and negative ions
- High melting/boiling points (low volatility) -> strong attractive forces between closely packed ions in giant ionic lattice (takes a lot of energy no break bonds)
- When solid -> can’t conduct electricty but do conduct when aqueous or molten -> ions are mobile and carry electric charge

Question 25

Covalent bond

Answer 25

Pair of electrons shared between two atoms to a noble gas electron configuration

Question 26

Covalent compund properties

Answer 26

- Low melting/boiling points (high volatility) -> intermolecular forces are weak - Don't conduct electricty -> don't have ions, only uncharged molecules

Question 27

The 3 types of giant covalent structures

Answer 27

Graphite Diamond Silicon

Question 28

Graphite: description

Answer 28

- Black, shiny solid - Each carbon atom forms 3 covalent bonds -> sheets of carbon atoms arranged in hexagons

Question 29

Graphite: properties

Answer 29

- High melting/boiling point -> covalent bonds in hexagon need loads of energy to break - Conducts electricity -> each carbon atom has one electron that's delocalised which can move and carry electric charge: Graphite often used for electrodes - No covalent bonds between layers so they can slide over eachother -> this makes graphite soft and slippery: graphite used as lubricant material

Question 30

Diamond: description

Answer 30

- Transparent colourless crystals - Each carbon atom forms four covalent bonds -> tetrahedral structure formed

Question 31

Diamond: properties

Answer 31

- High melting/boiling point -> strong covalent bonds need lots of energy to break - Very hard-> covalent bonds hold atoms in rigid lattice structure: Diamond used as cutting tool - Doesn't conduct electricity -> no free electrons

Question 32

Silicon (IV): Description

Answer 32

- Similar giant tetrahedral lattice to diamond - Silicon atoms positioned like carbon atoms in diamons, with an oxygen atom between each one

Question 33

Silicon (IV): properties

Answer 33

- High melting/boiling point -> strong covalent bonds need loads of energy to break - Hard -> covalent bonds hold atoms in rigid lattice structure - Doesn't conduct electricity -> no free electrons

Question 34

Metallic bonding

Answer 34

Electrostatic attraction between the positive ions in a giant metallic lattice and a 'sea' of delocolised electrons which holds atoms together in a regular structure

Question 35

Physical properties of metallic bonding

Answer 35

- Good electrical conductivity: delocolised electrons are free to move and carry electric charge - Ductility and malleability: positive ions in metal arranged regularly in layers, when force applied layers can slide over ecah other

Question 36

Giant ionic lattice

Answer 36

Regular arrangement of alternating positive and negative ions