Periodic table

Question 1

s block

Answer 1

Groups 1&2- outer electrons in the s orbital

Question 2

P block

Answer 2

groups 3-0
Outer electrons in p orbital

Question 3

D block

Answer 3

transition metals- outer electrons in d orbital

Question 4

ionisation energy in the periodic table

Answer 4

General increase across a period. There is an increase in nuclear charge in the same energy level so there is little extra shielding and therefore a greater attraction between a nucleus and outer electrons

Question 5

ionisation energy in Group 2 and 3

Answer 5

Decrease between Group Two and three. Group-Three elements the electron is in a new subshell of slightly higher energy level and is partially shielded by s-electrons

Question 6

ionisation energy between Group Five and six

Answer 6

Decrease between five and six. In group six electron is removed from an orbital containing a pair of Electrons. The repulsion between these electrons makes an electron easier to remove. in group five the electron is removed from a singly occupied orbital

Question 7

ionisation energy down a group

Answer 7

Decreases down a group. Her electron has increased shielding from inner electrons and is further from the nucleus. Outweighs the increase in the nuclear charge

Question 8

Electronegativity across a period

bonding elecrons

Answer 8

Increases across a period. increase In nuclear charge but the bonding electrons are always shielded by the same inner electrons so there is a greater attraction between nucleus and bonding pair

Question 9

Electronegativity down a group

bonding elecrons

Answer 9

Decreases down a group. Bonding electrons have increased yielding from the nucleus so the attraction between nucleus and bonding electrons decreases

Question 10

Metals- melting and boilng temperatures

Answer 10

Have metallic bonding, there is an increase because the metallic bonding gets stronger. Ions have a greater charge and there is an increased number of delocalized electrons

Question 11

Giant covalent structures eh. Silicon boron

Answer 11

Each atom is bonded covenantly to four other atoms and a large amount of energy is needed to break all these bonds

Question 12

Simple molecular substances eh. P, S, Cl

Answer 12

Although the Covalent bonds between atoms in the molecules are strong the intermolecular forces holding the molecules together are weak and do not need much energy to break

Question 13

Argon

Answer 13

Lowest melting boiling temperature because it exists as separate atoms held together by very weakened Induced dipole - induced dipole forces

Question 14

Electron transfer- half equations

Answer 14

oxidation: Eg. Mg—> Mg2+ + 2e
Reduction: Eg. Cu2+ + 2e —> Cu

Question 15

Group one metals with cold water

Answer 15

Form a hydroxide and hydrogen EG. Sodium
2Na + 2H2O—> 2NaOH + H2

Question 16

Lithium’s reaction with water

Answer 16

Floats on the water, gently fizzing

Question 17

Sodium’s reaction with water

Answer 17

Sodium melts into a bowl that dashes around the surface

Question 18

Potassium’s reaction with water

Answer 18

Potassium melts into a ball and catches fire

Question 19

Cesium’s reaction with water

Answer 19

caesium explodes and shatters the glass container

Question 20

Group two metals reaction with water

Answer 20

React less vigorously and hydroxide and hydrogen are formed
eg. Calcium
Ca + 2H2O —>Ca(OH)2 + H2

Question 21

Calcium’s reaction with water

Answer 21

Calcium produces a steady stream of bubbles and the liquid goes cloudy as a white participate of calcium hydroxide forms

Question 22

Barium’s reaction with water

Answer 22

barium produces greater Efveresscence and the solution is clearer since barium hydroxide is more soluble

Question 23

Magnesiums reaction with water

Answer 23

Magnesium reacts with steam to produce the oxide and hydrogen

Question 24

Trends in reactivity

g2

Answer 24

Reactivity increases as you go down the group
this is because when the S block metals react they lose electrons to form positive ions.
Since ionisation energy decreases down a group, the energy needed to form positive ions decreases. This leads to lower activation energies and therefore faster reactions

Question 25

G1 more reactive than G2

Answer 25

Because Group One metals lose only one electron while group 2 will lose two electrons

Question 26

Reaction with acids

Answer 26

All group two metals react vigorously with hydrochloric acid to produce a colourless solution of metal chloride and bubbles of hydrogen Eg. Mg Mg + 2HCL---> MgCl2 + H2 Reactivity increases down a group Only magnesium can react with sulfuric acid because other members have been soluble sulphates Group 1 metals are too reactive to be added directly to acids

Question 27

Group 2- Reaction with oxygen

Answer 27

Apart from magnesium, all group two metals tend to burn with a characteristic flame. All G2 metals burned to form solid white oxides Eg. 2Mg +O2---> 2MgO

Question 28

groups 1- reaction with oxygen

Answer 28

Group One metals also form white solids and burn with a characteristic flame Eg. 4Li + O2 ---> 2Li2O

Question 29

Oxides and hydroxides - s block metal oxides

Answer 29

( metal oxides are basic) (non metal oxides are acidic) All the s block metal oxides are strong bases and they neutralise acids to form a salt and water Eg. MgO + 2HCl ---> MgCl2 +H2O Other group two hydroxides are not very solid balls so saturated solutions of these hydroxides are only weakly basic because the concentration of hydroxide ion is very low

Question 30

G1- oxides and hydroxides

Answer 30

G1 oxides And barium oxide react w water to form a soluble hydroxide Eg. Na2O + H2O ---> 2NaOH HydroxideS are soluble so are alkalis

Question 31

test for cations

Answer 31

all S-block elements apart from magnesium can be identified by a flame testable to stop a clean metal wire or splint is moistened with hydrochloric acid dipped in the compound and held in a non-luminous Bunsen flame

Question 32

Flame tests

Answer 32

Li+- Red Na+- orange yellow K+- lilac Mg2+- no colour Ca2+- brick red Sr2+- crimson Ba2+- apple green

Question 33

Solubility in water

Answer 33

All Group One compounds are soluble but many group two compounds are not

Question 34

Trends for group two compounds - solubility

Answer 34

- All nitrates are soluble - All carbonates are insoluble - The hydroxides become more soluble as you go down the group so magnesium hydroxide is insoluble whilst barium is soluble Mg2+(aq) + 2OH-(aq) ---> Mg(OH)2 (s) - The sulphates become less soluble as you go down the group Ba2+(Aq) + SO42- (aq)--> BaSO4 (s) - all pretcipirates ate white

Question 35

Thermal stability of hydroxide and carbonates- Group 2 hydroxides'

Answer 35

All group two hydroxides decompose on heating to the oxide and steam Eg. Ca(OH)2(s) ---> CaO (s) + H2O (g) Thermal stability increases down a group so Hydroxides have to be heated more strongly before they will decompose

Question 36

Himal stability of hydroxide and carbonates - group two carbonates

Answer 36

all group two carbonates decompose on heating to the oxide and carbon dioxide Eg. MgCO3(s) ----> MgO(s) + CO2(g) Fairmont stability increases as you go down the group Presence of CO2 turns limewater cloudy

Question 37

Chemistry of group seven halogens and halides | at room emp

Answer 37

Halogens produce salt called halides At room temperature chlorine is a green gas, bromine a red brown liquid and iodine a grey solid

Question 38

Volatility down a group

Answer 38

Ask the number of Electrons increases with atomic number, there is an increase in the induced dipole - induced dipole intermolecular forces holding the diatomic molecule together. Therefore the melting and boiling temperatures increase as you go down the group. A substance that forms vapours easily are called volatile. Since with the low boiling temperature has high volatility and volatility decreases down the group

Question 39

Trends in reactivity with group seven

Answer 39

The halogens react by gaining electrons to form negative halide ions. They gain electrons during reactions or halogens are reduced and they oxidise with other substances As you go down the group's outer electrons are shielded more and further from the nucleus so it's harder to attract electrons and both reactivity and oxidising power decreases down the group

Question 40

Reaction with a metal and halogen to form a white metal halide

Answer 40

eg. Sodium + cchlorine gas= white sodium chloride 2Na +Cl2--> 2NaCl

Question 41

Reaction with iron wool

Answer 41

Ironwall also bends directly in chlorine or bromine vapour to give iron (III) halide 2Fe +3Br2---> 2FeBr3 When it burns in iodine vapour it only produces iron (II) iodide since iodine is less reactive and it's a weaker oxidising agent Fe+ I2 ---> FeI2

Question 42

Displacement reactions

Answer 42

A halogen in a higher position in the group will oxidise a halide ion from a lower in the group since oxidising powers decrease down a group Eg. Cl2(aq) + 2Br- (aq) ---> 2Cl- (aq) + Br2(aq) 0 -1 -1 0

Question 43

Task for hslide ions silver nitrate test

Answer 43

If you start from a solid it must be first dissolved in water A few drops of nitric acid is added first to make sure that any other anions especially carbonates are removed, as they would also form precipitates

Question 44

Silver nitrate test observation

Answer 44

Cl- forms white precipitate Br- forms cream I- forms pale yellow Eg. Ag+(aq) + Cl-(aq) ----> AgCl(s)

Question 45

Aqueous ammonia to the precipitate

Answer 45

Sometimes it can be difficult to tell the difference between the precipitates so to distinguish between them aqueous ammonia is added to the precipitate

Question 46

Aqueous ammonia observation

Answer 46

AgCl- Precipitate dissolves in dilute ammonia AgBr- Precipitate does not dissolve much in dilutes ammonia but dissolves in concentrated ammonia AgI- Participate is insoluble in dilutes and concentrated ammonia

Question 47

Chlorine added to water

Answer 47

Chlorine is commonly added to water as a gaseous element and the equilibrium is established Cl2 + H2O --> HCl + HOCl

Question 48

User of the chlorate ion

Answer 48

ClO- Kills bacteria and other microbes so adding chlorine to water makes it safe to drink or swim. Chlorination is used to prevent the outbreak of serious diseases like typhoid and cholera - Highly toxic and can react with naturally occurring organic compounds found in water supply to form chlorinate hydrocarbons which can cause liver and kidney cancer - "mass medication"

Question 49

Fluoride added to water

Answer 49

To reduce tooth decay by preventing cavities. Water fluoridation reduces cavities in children's but its effectiveness in adults is less clear - Although fluoridation can cause dental fluorosis leading to tooth discoloration there is no clear evidence of other adverse effects - " mass medication"