TOPIC 6 Groups In The Periodic Table

Question 1

What type of reactions do group 7 elements take part in and why?

Answer 1

Displacement reactions as more reactive halogens displaces less reactive halogens in an aqueous solution of its salt.

Question 2

Chlorine water+ potassium iodide

Answer 2

Potassium chloride + iodine

Question 3

Write out the balanced equation for chlorine + potassium iodide

Answer 3

Cl2 + 2KI > I2 + 2KCl

Question 4

What happens during halogen displacement?

Answer 4

An Electron is passed from the less reactive halogen to the more reactive halogen, meaning the less reactive ones are discharged and can exist as an atom.

Question 5

What happens as you go down the halogen group and why?

Answer 5

Reactivity decreases as the outer-shell becomes further from the nucleus and so attraction decreases between nucleus and outer electrons so electrons are gained less easily.

Question 6

Oxidation

Answer 6

Loss of electrons

Question 7

Reduction

Answer 7

Gain of electrons

Question 8

Oxidising agent

Answer 8

Accepts electrons and is reduced

Question 9

Reducing agent

Answer 9

Donates electrons and gets oxidised

Question 10

Redox reactions

Answer 10

Reactions where reduction and oxidation happen simultaneously.

Question 11

Rusting word equation

Answer 11

Iron + oxygen + water > hydrated iron oxide (rust)

Question 12

2 main ways to prevent rusting

Answer 12

Barrier and sacrificial method

Question 13

Barrier methods

Answer 13

Painting/coating with plastic.

Oiling/ greasing (when moving parts are involved)

Question 14

Sacrificial method

Answer 14

Use a more reactive metal with it. (Coating or blocks)

Question 15

Group 1?

Answer 15

Alkali metals >>>
Lithium
Sodium
Potassium 
Rubidium
Caesium
Francium

Question 16

Alkali metal + water

Answer 16

> > metal hydroxide (alkali) + hydrogen

Question 17

How many outer-electrons do alkali metals have? What does this mean?

Answer 17

1. This means that alkali metals are v reactive as are keen to give away their outerelectron and maintain a full outer shell. They then become a positive ion.

Question 18

Physical properties of alkali metals

Answer 18

Low melting/boiling points in comparison to other metals.
Very soft.
Very reactive.
Dull colored.

Question 19

Balanced equation of lithium + oxygen

Answer 19

2Li + O2&raquo_space; Li2O

Question 20

What happens as you go down group 1? Why?

Answer 20

Alkali metals increase reactivity, boiling points and atomic radius. It also increases density. This is because, the larger an atom becomes, the further away the outer-electron is from the nucleus. This decreases attraction between the nucleus and outerelectron and so means the outerelectron is easier to remove (more reactive).

Question 21

What type of reaction is alkali metals+ water?

Answer 21

Exothermic as it gives out heat. The flame is the hydrogen on fire.

Question 22

Balanced equation of sodium + water

Answer 22

2Na + 2H2O &raquo_space; 2NaOH + H2

Question 23

How does an alkali metals period affect its reaction with water?

Answer 23

As you go down group 1, speed and violence of the production of metal hydroxide increases.

Question 24

What color does the left over solution from alkali metals and water turn universal indicators?

Answer 24

Purple as its an alkaline solution.

Question 25

Test for hydrogen

Answer 25

Squeaky pop test. Put glowing splint in test tube of gas. If it makes a popping sound, hydrogen is present.

Question 26

What color is the flame when an alkali metal is put in water?

Answer 26

Lilac

Question 27

What are the group 7 elements?

Answer 27

Halogens:
Fluorine 
Chlorine 
Bromine
Iodine 
Astatine

All have 7 outer electrons

Question 28

What type of molecule are halogens? What are their bonding?

Answer 28

They are diatomic molecules joined by covalent bonds which gives both atoms a full outershell.

Question 29

What happens as you go down group 7

Answer 29

The melting point/boiling points increases. Reactivity decreases, this is because bigger atomic radius mean that there’s less force of attraction between the nucleus and outerelectrons and so less attraction to attract an extra electron to maintain a full outershell.

Question 30

Chlorine characteristics and how do you test for it?

Answer 30

Fairly reactive, poisonous green gas.

It will turn damp blue litmus paper momentarily red (as Cl is acidic) and then bleach it white.

Question 31

Characteristics of bromine

Answer 31

Poisonous, red, brown liquid that gives off an orange vapour at room temperature.

Question 32

Characteristics of iodine

Answer 32

Dark grey crystalline solid which gives off purple vapor when heated.

Question 33

Metal + halogen

Answer 33

(Reacts vigorously) > metal halide (salt)

Question 34

Halogen + hydrogen

Answer 34

> hydrogen halide

Question 35

What are group 0?

Answer 35

Noble gases are helium, neon, argon, krypton, xenon, radon

Question 36

Characteristics of noble gases

Answer 36

Are all colourless, inert gases at room temp.
They are monatomic. 
Nonflammable.
Hard to observe.
Low density.

Question 37

Why are noble gases inert?

Answer 37

Because they contain a full outershell so have no need to gain/lose electrons to maintain a full outershell.

Question 38

What are noble gases used for?

Answer 38

ARGON is used in filament lightbulbs as it provides and inert atmosphere and so will stop the v hot filament from burning up in the air.
The same principle is used in camera bulbs with argon, krypton and xenon to stop the flash filament from burning up in high temp flashes.
ARGON and HELIUM can be used to protect metals that are being welded as it stops the hot metal from reacting with the oxygen.
HELIUM is used in airships and party balloons as He has a lower density than air which makes the balloon float, it’s also nonflammable so is safer to use than hydrogen.

Question 39

What happens as you go down group 0?

Answer 39

Melting/boiling points and density INCREASE as you go down group 0. Reactivity is the same throughout as they all have full outershells.