Periodicity (not finished)

Question 1

What do all the members of a period have in common

Answer 1

Same number of electron shells
Similar chemical characteristics

Question 2

What is periodicity

Answer 2

The repeating properties of elements

Question 3

How do 1st ionisation energies change going down group 2

Answer 3

Getting lower due to the increasing distance between the nucleus and the outer electrons

Question 4

How do atomic radii change going down group 2

Answer 4

Increasing as there are a greater number of electron shells

Question 5

How does melting point change going down group 2

Answer 5

Lower as the bond strength is weaker due to the increasing atomic radii

Question 6

How does electronegativity change going down group 2

Answer 6

Decrease as the ionic radii increases and the outer electrons are further away from the nucleus

Question 7

How does the reaction with water change going down group 2

Answer 7

More reactive as less energy is required to remove the outer electrons

Question 8

What is the general equation for the reaction between group 2 metals and water

Answer 8

M + 2H20 -> M(OH)2 + H2

Question 9

Why are the solutions formed between the reaction of group 2 metals and water alkaline

Answer 9

The formation of OH- ions

Question 10

Why does the pH of the group 2 hydroxides increase going down the group

Answer 10

More OH- ions in the water

Question 11

How does the solubility of group 2 hydroxides change going down the group

Answer 11

Become more soluble

Question 12

How does magnesium react with cold water

Answer 12

Very slowly

Question 13

How does magnesium react with steam and how do the products of this reaction differ to the reactions of other group 2 metals with cold water

Answer 13

Reacts much faster with steam but no hydroxide is formed as it decomposes

Question 14

What is the equation of the reaction of magnesium and steam
What are the observations for this reaction

Answer 14

Mg + H20 (g) -> MgO + H2
Burns with a bright white flame to form a white solid

Question 15

What happens to the group 2 metals when they react with water (OIL RIG)

Answer 15

They are oxidised and lose electrons

Question 16

What is the equation for the reaction between chlorine and water

Answer 16

Cl2 + H2O -> (reversible) HCl + HOCl

Question 17

How does the solubility of group 2 sulfates change going down the group

Answer 17

Decreases

Question 18

Name and explain one use of barium sulfate that relies on it being insoluble

Answer 18

Used in barium meals for aiding diagnosis of problems within the GI tract as it acts as a contrast medium to highlight any abnormalities in soft tissues

Question 19

What is the basis of the test for sulfates

Answer 19

The fact that barium sulfate is insoluble

Question 20

Describe the chemical test for sulfates

Answer 20

Add barium chloride and hydrochlorid acid, or barium nitrate and nitric acid. If the unknown is a sulfate, it will give a white ppt of barium sulfate

Question 21

In the test for sulfates, why is an acid also used (usually HCl)

Answer 21

to get rid of any carbonate, ions, or any other unwanted precipitates which also precipitate in the absence of acid

Question 22

What would the equation be for the hydrochloric acid reacting with the carbonate in the test for sulfates

Answer 22

2HCl + BaCO3 -> BaCl2 + CO2 + H2O

Question 23

What are bases

Answer 23

Substances that react with acids to form a salt and water

Question 24

How can magnesium hydroxide be used as an antacid

Answer 24

Milk of magnesia is an antacid containing a suspension of magnesium hydroxide suspended in a liquid

Question 25

What is a suspension

Answer 25

Small particles of insoluble solid suspended in a liquid

Question 26

Why does the magnesium hydroxide in milk of magnesia form a suspension and not a solution

Answer 26

It is insoluble

Question 27

Why does magnesium hydroxide relieve indigestion

Answer 27

Reacts with excess stomach acid and neutralises it

Question 28

Which hydroxide be used to treat acidic soils

Answer 28

Calcium hydroxide

Question 29

What is the equation of calcium hydroxide treating acidic soils

Answer 29

Ca(OH)2 + 2H+ -> Ca2+ + 2H20

Question 30

Which acidic gas is produced when sulfur in fossil fuels is burnt

Answer 30

Sulfur dioxide

Question 31

Write an equation for the formation of sulfur dioxide from fossil fuels

Answer 31

S + O2 -> SO2

Question 32

What environmental issue can sulfur dioxide cause

Answer 32

Acid rain

Question 33

How do flue gases help to remove SO2

Answer 33

They are passed through filter beds of calcium oxide and react with the SO2 to remove it

Question 34

Write an equation for the removal of SO2 using flue gases Calcium carbonate could be used in a similar way

Answer 34

CaO + SO2 -> CaSO3 CaCO3 + SO2 -> CaSO3 + CO2

Question 35

What are the 2 ways to extract titanium from titanium oxide

Answer 35

Reduction by sodium Reduction by magnesium

Question 36

Equation for extraction of titanium with reduction by sodium

Answer 36

TiCl4 + 4Na -> Ti + 4NaCl

Question 37

Equation for extraction of titanium with reduction by magnesium

Answer 37

TiCl4 + 2Mg -> Ti + 2MgCl2

Question 38

Why can't you extract titanium using carbon

Answer 38

Titanium will react with carbon to produce titanium carbide which makes the metal more brittle

Question 39

How does the extraction of titanium with reduction by sodium work

Answer 39

Titanium chloride added to a reactor with pure sodium Heated to around 1000 degrees Left to cool for several days Mixture is crushed and washed with dilute HCl to remove the sodium chloride

Question 40

How does the extraction of titanium with reduction by magnesium work

Answer 40

Similar to sodium but just with magnesium

Question 41

Why is titanium so expensive

Answer 41

Because magnesium is also expensive to extract because electrolysis is required

Question 42

How does atomic radius change across a period

Answer 42

Gets smaller

Question 43

What is the definition for electronegativity

Answer 43

The ability for an atom to attract a shared pair of electrons to itself in a covalent bond

Question 44

Describe the trend in electronegativity across the 3rd period

Answer 44

Increases due to more protons in nucleus, same shielding, smaller atoms and greater attraction

Question 45

What are the reasons for an ionisation energy requirement drop across a period

Answer 45

A change in electron shell Electron repulsion

Question 46

Reaction and equation of sodium with air

Answer 46

Burns with a solid yellow flame to form a white solid 4Na + O2 -> 2Na2O

Question 47

Reaction and equation of magnesium with air

Answer 47

Burns with a bright white flame to form a white solid 2Mg + O2 -> 2MgO

Question 48

Reaction and equation of aluminium with air

Answer 48

Aluminium itself doesn't react because it has an oxide coating. This can be remedied by using aluminium powder (max SA) Burns with a bright white flame to form a white solid 4Al + 3O2 -> 2AlO3

Question 49

Reaction and equation of silicon with air

Answer 49

Requires powdered magnesium to reach the required activation energy Glows red and a white solid is formed Si + O2 -> SiO2

Question 50

Reaction and equation of phosphorus with air

Answer 50

Burns with a bright white flame for a prolonged period and forms a white solid P4 + 5O2 -> P4O10

Question 51

Reaction and equation of sulfur with air

Answer 51

Burns with a bright blue flame making a colourless choking gas S + O2 -> SO2