The Periodic Table

Question 1

Define periodicity?

Answer 1

A pattern of repeating trends in the periodic table

Question 2

How do they measure the atomic radius ?

Answer 2

Bcz electrons dont have a clear cut of point instead they measure the distance between the nuclei of 2 identical covalently bonded atoms and half it

Question 3

What is the periodicity in atomic radius across a period and why?

Answer 3

Atomic radius decreases as the nuclear charge goes up so electrons in outer shell are pulled more closely and shielding remains similar

Question 4

What is the periodicity of atomic radius Down a group?

Answer 4

Atomic radius increases down a group due to more electrons therefore shells and more shielding

Question 5

What is the trend in FIE and exceptions?

Answer 5

The same as previously
But exceptions FIE decreases is the electron is taken out of a higher energy sub shell then previously or the electron is taken out from an orbital containing 2 electrons (with opposite spins)

Question 6

Where are the location of specific elements on the periodic table?

Answer 6

Metals on the left and non metals on the right in between are the metalloids/semi metals

Question 7

Describe metallic bonding and name of structure?

Answer 7

Electrons in the outer shell delocalise forming a sea of delocalised electrons and the remaining atom forms a cation these 2 attract eachother due to electrostatic forces of attraction
Giant metallic lattice

Question 8

How does metallic bonding affect the properties of metals?

Answer 8

Melting point=lots of forces to break so high melting point
Can conduct electricity=delocalised electrons act as mobile charge carriers
Solubility= metals are insoluble in water due to the solvent unable to come in between the IF but they may react instead

Question 9

Explain the giant covalent structure of diamond and the properties it gives?

Answer 9

Each carbon atom is covalently bonded to 4 other carbon atoms to form a tetrahedral structure bond angle 109.5
Very high melting point due to covalent bonds
Insoluble cannot conduct electricity as no electrons that can delocalise so no mobile charge carriers

Question 10

Describe the structure of graphite and the properties?

Answer 10

Each carbon atom covalently bonded to 3 other carbons forming triginal planar structure bind angle 120 and delocalises the remaining electron
High melting/boiling point
Can conduct electricity due to delocalised electrons acting as mobile charge carriers
Still insoluble

Question 11

What structure do simple molecular substances form?

Answer 11

They form a simple molecular lattice
-low melting and boiling point
-cannot conduct
-solubility varies on polarity

Question 12

What are group 2 metals called?

Answer 12

The alkali earth metals

Question 13

How do the alkaline earth metals react?

Answer 13

The all contain 2 electrons in the s orbital so they act as reducing agents getting oxidised to 2+ ion

Question 14

Explain reactivity of group 2 metals down the group?

Answer 14

Reactivity increases due to reducing powers increasing and first ionisation energy decreasing

Question 15

What do u produce when reaching group 2 metals wiyh oxygen?

Answer 15

Metal oxide
U see a bright white light

Question 16

What do u get when reacting group 2 metals with water?

Answer 16

Metal hydroxide + hydrogen gas

Question 17

What do u get when reacting group 2 metals with dilute acid?

Answer 17

Salt and hydrogen gas

Question 18

What is the trend of solubility in group 2 metal hydroxides?

Answer 18

Solubility increases down the group

Question 19

How do u make group 2 hydroxide?

Answer 19

U can react the group 2 metals wity water
But u can also react the group 2 oxide with water aswell

Question 20

Why does alkalinity increase with solubility?

Answer 20

If solubility increases then the amount of the metal hydroxide that can disassociate to the OH- ion increase the alkalinity depends on the concentration of the OH- ion

Question 21

What are the uses of some group 2 hydroxides ?

Answer 21

Solid Calcium hydroxide used in agriculture to neutralise acidic soil for crops
Magnesium hydroxide (aq) milk of magnesia used to treat excess HCl in the stomach
Also can use calcium carbonate but NOT calcium hydroxide as the alkalinity damages the tissue of the throat

Question 22

What is the trend in group 2 sulphate solubility?

Answer 22

Solubility decreases down the group

Question 23

How is barium sulphate used?

Answer 23

Barium sulphate is insoluble but can absorb X rays very well so patients undergoing an intestinal exam have a barium meal which can enable to see the digestive system and since it’s insoluble it doesn’t enter then blood stream

Question 24

How can barium chloride be used ro test for sulphates?

Answer 24

Barium chloride disassociates in water to form the Ba 2+ ion and Cl- ion
The barium then reacts with the sulphates to form barium sulphate which is insoluble so a white precipitate forms

Question 25

What is a key point about testing for sulphate ions?

Answer 25

The barium can react with existing carbonate ions so before the test we add dilute nitric or hydrochloric acid to react with the carbonates forming CO2 gas that evaporates Barium carbonate is also a white precipitate and can give false results

Question 26

What are the colours of the halogens?

Answer 26

Fluorine= pale yellow gas Chlorine= pale green gas Bromine= brown/ orange liquid Iodine = black grey solid

Question 27

Decribe the trend in boiling point and electronegativity in the halogens?

Answer 27

Melting and boiling point increases down the group because only can de bald forces act in halogens the increasing electrons make the van de valls force stronger Electronegativity decreases down the group

Question 28

What happens in a displacement reaction in halogens?

Answer 28

Aqueous halogen reacts with aqueous metal halide more reactive halogen displaces the halide in the metal halide

Question 29

How do u determine what halogen has been displaced?

Answer 29

Because the colours of the halogens can get mixed up we add a non polar organic solvent such as cyclohexane that the halogens dissolve in Chlorine =pale green Bromine= orange Iodine = violet

Question 30

What is a disproportionation reaction?

Answer 30

A reaction where the same element has been oxidised and reduced

Question 31

What is the reaction between chlorine and water?

Answer 31

Forms chloric (I) acid and hydrogen chloride

Question 32

What are the pros and cons of chlorinated drinking water?

Answer 32

The chloric acid is what kills the bacteria in the water preventing anh water born diseases such as cholera Cons is chlorine is a toxic gas and must be delt with carefully at water treatment facilities Also the chlorine in water can react with naturally occurring hydrocarbons such as from decaying materials and the chlorinated hydrocarbons can increase risk of cancer in humans But since chlorine isn’t that soluble in water only a small amount of products form

Question 33

What is the reaction of chlorine with dilute cold sodium hydroxide?

Answer 33

Also a disproportionation reaction Products are sodium chlorate +sodium chloride +water Sodium chlorate is a very powerful oxidising agent and is used as household bleach

Question 34

What is the reaction group 1 metal halide and concentrated sulfuric acid? MAKE SURE TO WEITE THE EQUATIONS OUT

Answer 34

Cl only one reaction All them produce sodium hydrogen sulphate + hydrogen (halogen in this case chlorine) appears as misty fumes Only one reaction which isn’t redox because chlorine is a weak reducing agent Bromine —> more powerful reducing agent therefore another 2nd reaction happens which is redox 1st reaction remains the same 2nd reaction Hydrogen bromide reacts with the sulfuric acid again and makes Br2 + H2O and sulfur dioxide (toxic choking gas) Iodine even more powerful reducing agent so another 3rd redox reaction takes place Sulfur dioxide reacts with hydrogen bromide producing bromine and hydrogen sulfide (rotten egg smell)

Question 35

How do u test for halide ions?

Answer 35

Add silver nitrate it dissociates in water to produce the silver ion and the nitrate ion then reacts with the halides forming a silver halide which is insoluble deepening on the colour of the precipitate tells u which halide bonded

Question 36

What are the colours of the silver halides?

Answer 36

Cl= white precipitate Br= cream precipitate I = pale yellow

Question 37

What do u do because the colours are similar?

Answer 37

U add either concentrated or aqueous ammonia Silver chloride —> dissolves in dilute aq ammonia Silver bromide—> dissolves in concentrated aq ammonia Silver iodide —> doesn’t dissolve in either

Question 38

What happens if carbonates or sulphates are present and how do u avoid it?

Answer 38

Silver carbonate or sulphate can form which is also a white precipitate which can give false results To remove or test for carbonates we add dilute nitric acid and bubble any gas into limewater to see if it turns cloudy keep bubbling Untill no more gas forms For sulphates we add barium nitrate this dorms barium sulfate a white precipitate keep adding excess to ensure all sulphates are removed then filter precipitate