C1 - Atomic Structure And The Periodic Table

Question 1

Information on filtration.

Answer 1

Filtration separates insoluble solids from liquids
Used if your project is an insoluble solid that needs to be separated
Solid impurities in the reaction mixture can be separate with filtration ‘purification’

Question 2

Information on evaporation

Answer 2

Separates soluble solids from solutions
Solution into evaporation dish
Slowly heat solution > solvent evaporates and solution will get more concentrated > crystals will start to form
Only use if salt doesn’t decompose when heated otherwise have to use crystallisation

Question 3

Information on crystallisation

Answer 3

Pour solution into evaporation dish and gently heat
Some solvent will evaporate and solution becomes more concentrated, once crystals start to form, leave it to cool and the salts will form crystals as it becomes insoluble in cold, concentrated solutions

Question 4

Filtration and crystallisation to separate rock salt

Answer 4

Mixture of salt and sand, salt dissolves, sand doesn’t.
Grind mixture and make sure salt crystals are small
Pour into water and stir until salt dissolved
Filter mixture to remove sand
Evaporate water so salt forms dry crystals

Question 5

Number of protons =

Answer 5

Number of electrons

Question 6

Why do atoms have no charge

Answer 6

Protons and electrons charge cancel each other out

Question 7

Relative mass and charge of proton, neutron and electron

Answer 7

Electron mass of almost 0, charge of -1
Proton mass of 1, charge is +1
Neutron mass of 1, charge is 0

Question 8

What’s the atomic number

Answer 8

How many protons

Question 9

What’s the mass number

Answer 9

Total number of protons and neutrons

Neutrons = atomic number - mass number

Question 10

What’s an isotope

Answer 10

Different forms of the same elements
Same protons but different number of neutrons
E.g carbon 12 and carbon 13

Question 11

What are elements

Answer 11

Elements consists of atoms with the same atomic number.

Each atom has a different number of protons, neutrons and electrons. The proton amount determines what atom it is

Question 12

Why is there a relative atomic mass

Answer 12

As many elements exists as isotopes

Question 13

Formula of relative atomic mass (Ar)

Answer 13

Relative atomic mass = sum of (isotope Abundance x isotope mass number)/ sum of abundance’s of all isotopes

Question 14

Example of relative atomic mass calculation

Answer 14

Copper
Cu 63 abundance of 69.2%
Du 65 abundance of 30.8%

(69.2 x 63) + (30.8 x 65) / 69.2 + 30.8 = 63.6

Question 15

What are compounds

Answer 15

Two or more atoms joined together to make a compound
Substances formed from 2 or more elements.
Atoms in fixed proportions and chemically bonded

Question 16

Why is it hard to separate compounds

Answer 16

Because you need a chemical reaction
Properties of a compound are different to elements
Compound with metals and non-metals consist of ions
Compounds with non-metals consist of molecules
Compounds can be shown with a formula

Question 17

Common compound formulas of ammonia, sodium chloride, carbon monoxide, hydrochloric acid, calcium chloride, sodium carbonate and sulphuric acid

Answer 17

Ammonia - NH3 
Sodium chloride - NaCl 
Carbon monoxide - CO 
hydrochloric acid - HCl 
Calcium carbonate - CaCl2
Sodium carbonate - NaCO2
Sulphuric acid - H2SO4

Question 18

What are chemical equations

Answer 18

Equations that show a chemical reaction

Symbol equations are shorthand

Question 19

What is meant by balancing an equation

Answer 19

Same number of atoms on each side

Question 20

John Dalton to atom

Answer 20

Described atoms as solid spheres

Question 21

JJ Thomson on atoms

Answer 21

Atoms contained smaller electrons - plum puddin

Question 22

Rutherford on atoms

Answer 22

Alpha particle scattering experiment
Fired positively charged alpha particles at gold foil - most of through
Some deflected, some changed direction kind of due to alpha particles hitting tiny nucleus
Therefore atom mostly empty space

Question 23

Bohrs nuclear Model

Answer 23

Suggested atoms in shells - electrons orbit at fixed shells(energy levels)

Question 24

James Chadwick on atoms

Answer 24

Provided evidence for neutrons

Question 25

Where’s the lowest energy level

Answer 25

Closest to the nucleus - always filled first

Question 26

Electronic structure of electrons

Answer 26

Always 2, 8, 8, 8 etc

Question 27

Why is it better to have a full outer shell

Answer 27

So the atom doesn’t want to react to fill it - unstable

Question 28

Early 1800s periodic table

Answer 28

Elements arranged by atomic mass - no idea on protons, neutrons or electrons Only measure relative atomic mass

Question 29

Dimitri Mendeleev’s periodic table

Answer 29

1869 Mendeleev took 50 known elements and arranged them and left gaps He put in order of atomic mass but switched order if properties didn’t match E.g iodine has a smaller mass, but placed after tellurium as it had similar properties to elements in that group Some gaps indicated undiscovered elements

Question 30

How did isotopes support mendeleev’s table

Answer 30

Proved not to order on relative atomic mass but to take into account properties Isotopes have different masses but same chemical properties

Question 31

Information on modern periodic table

Answer 31

Ordered in increasing atomic number - repeating properties Metals on left, non-metals on right Elements with similar properties form columns Vertical columns form groups

Question 32

What do group numbers on the period table tell you

Answer 32

Group number tells you how many electrons on the outer shell Group 1 = 1 electron Group 0 = full outer shell This is useful as atoms react depending on number of electrons in outer shell

Question 33

Rows are called...

Answer 33

Periods. Each new period represents another full outer shell of electrons

Question 34

Information on metal elements

Answer 34

Metal Elements form positive ions when reacted | They’re on the bottom and left of table

Question 35

Information on non-metal elements

Answer 35

Non-metals are far right and top | Don’t generally form positive ions when they react

Question 36

Why do atoms react

Answer 36

To try form a full outer shell of electrons - by gaining, loosing or sharing electrons

Question 37

How to metals to the left and bottom react

Answer 37

Left - Don’t have many electrons to remove - easier to remove electrons as there’s not as many Bottom - more electrons but they’re further away from nucleus so feel a weaker attraction - not much energy needed to remove so it’s feasible for these elements to form positive ions

Question 38

How do non-metals to the top and right react

Answer 38

Right - lots of electrons to remove Top- outer electrons close to the nucleus - strong attraction Therefore more likely to gain or share electrons so not as much energy is used to get rid of them

Question 39

Properties of metals

Answer 39

Metallic bonding Strong, can be bent or hammered(malleable) Good heat + electric conductors High boiling and melting points

Question 40

Properties of non-metals

Answer 40

``` No metallic bonding Dull looking Brittle Aren’t always solid at room temperature Lower density Don’t really conduct electricity ```

Question 41

What are group 1 metals

Answer 41

Alkali metals, they’re reactive soft metals

Question 42

List the Alkali metals(group 1)

Answer 42

Lithium Li, sodium Na, potassium K, rubidium Rb, caesium Cs, francium Fr

Question 43

Properties of group 1 alkali metals

Answer 43

1 electron in outer shell, very reactive soft and low density Increasing reactivity as you go down - electrons further from nucleus Lower melting and boiling points as you go down Higher relative atomic mass as you go down

Question 44

What do alkali metals form with non metals

Answer 44

Form ionic compounds Group 1 don’t need much energy to lose their outer electron - readily forms 1+ ion So easy they only ever react to form ionic compounds Compounds generally white solids that dissolve in water to form colourless solutions

Question 45

What happens when group 1 reacts with water

Answer 45

Vigorous reaction Li, Na and K float, move and fizz on surface. They produce hydrogen when reacting K and below ignite hydrogen with their energy

Question 46

Group 1 reaction with oxygen

Answer 46

Lithium oxide Sodium oxide or potassium peroxide Potassium peroxide or potassium superoxide

Question 47

Group 1 reaction with chlorine - what does it produce

Answer 47

Produces salt. Group 1 reacts vigorously when heated in chlorine gas to form white salts and metal chlorides Go down group = more vigorous

Question 48

What are the group 7 elements

Answer 48

Called halogens - all non metals and coloured vapours

Question 49

Group 7 coloured vapours and their reactive ness

Answer 49

Fluorine - very reactive, poisonous yellow gas Chlorine - fairly reactive, poisonous dense green gas Bromine - dense, poisonous red brown volatile liquid Iodine - dark grey crystalline solid or purple vapour There’s also astatine

Question 50

Properties of group 7 elements

Answer 50

All exist as molecules which are pairs of atoms As you go down - become less reactive as it’s harder to gain an electron - further away Higher melting/boiling points Higher relative atomic mass

Question 51

Halogens can form...

Answer 51

Molecular compounds Halogens share electrons via covalent bonding with other non-metals to achieve full outer shell Compounds that form when halogens react with non metals all have simple molecular structures

Question 52

What do halogens form with metals

Answer 52

Form ionic bonds Halogens with 1- Ions are halides when they bond with metals Compounds formed have ionic structures

Question 53

More reactive halogens will displace...

Answer 53

Less reactive ones Displacement reaction can happen between more reactive halogens and the salt of a less reactive one. E.g chlorine displace bromine and iodine form an aqueous solution of its salt Chlorine + potassium iodide -> iodine + potassium chloride

Question 54

What are group elements

Answer 54

All inert colourless gases

Question 55

Properties of group 0 elements

Answer 55

All eight electrons in outer (helium has 2) Outer shell energetically stable - don’t have to give up or gain electron Inert as they don’t react much - also non flammable Exist as monatomic gases - single atoms NOT bonded to each other All colourless at room temperature As you go down, increase boiling point, increase relative atomic mass Increase in boiling due to the number of electrons in each atom - greater inter molecule forces between them - harder to overcome