17 - Groups in the Periodic Table

Question 1

What is group 1 in the periodic table also known as?

Answer 1

Alkali Metals

Question 2

Give some examples of Group 1 elements:

Answer 2

• Hydrogen
• Lithium
• Sodium
• Potassium
• Rubidium
• Caesium
• Francium

Question 3

Where do Alkali Metals need to be stored?

Answer 3

In oil

Question 4

What are some physical properties of Alkali metals that are unique?

Answer 4

• Soft
• Low melting points
• Low densities

Question 5

What’s the general equation for an alkali metal reacting with water?

Answer 5

Alkali metal + water —> metal hydroxide + hydrogen

Question 6

Describe the reaction of lithium & water?

Answer 6

Bubbles fiercely on the surface

Question 7

Describe the reaction of sodium & water?

Answer 7

Melts into a ball & fizzes about on the surface

Question 8

Describe the reaction of potassium & water?

Answer 8

Bursts into flames & flies about the surface

Question 9

Describe the pattern in reactivity of the alkali metals

Answer 9

Reactivity of Group 1 elements INCREASES as you go down the group

Question 10

Describe the electronic configuration of all alkali metals:

Answer 10

• One electron in outer shell
  —> Gives similar chemical properties

Question 11

The more readily a metal loses its outer electrons…

Answer 11

…The more reactive it is

Question 12

Explain Group 1’s pattern of reactivity in terms of electronic
configurations:

Answer 12

The outer electron is more easily lost as its further from the nucleus
—> so its less strongly attracted to the nucleus & less energy is needed to remove it

Question 13

How can you predict the reactions of the group 1 elements?

And can you give an example?

Answer 13

By knowing the reactivity trend of Group 1

e.g. Rubidium/ Caesium is near the bottom of group 1. So you may predict that the reactions of these 2 elements will be the most violent

Question 14

What is Group 7 in the periodic table also known as?

Answer 14

The Halogens

Question 15

Give some examples of Group 7 elements:

Answer 15

• Fluorine
• Chlorine
• Bromine
• Iodine
• Astatine
• Tennessine

Question 16

What are some physical properties of The Halogens that are unique?

Answer 16

• Non - metals
• Diatomic molecules
  —> Sharing one pair of electrons in a covalent bond gives both atoms a full outer shell
• Melting points & Boiling points increase as you go down the group

Question 17

Why does the melting/boiling points of Halogens/Noble gases INCREASE as you go down the group?

Answer 17

• The Molecules become larger
• Intermolecular forces become stronger
  —> More energy is needed to overcome these forces

Question 18

What is the colour & the physical state of Chlorine at room temperature?

Answer 18

• Pale green
• Gas

Question 19

What is the colour & the physical state of Bromine at room temperature?

Answer 19

• Brown
• Liquid
• Gives off an orange vapour

Question 20

What is the colour & the physical state of Iodine at room temperature?

Answer 20

• Purple-Black
• Solid
• Gives off a purple vapour (when heated)

Question 21

How can you predict the reactions of the group 7 elements?

And can you give an example?

Answer 21

By knowing the reactivity trend of Group 7

e.g. Melting points increase down the group + colours get darker.
So Astatine will be a dark-coloured solid @ room temperature

Question 22

How would you test for Chlorine?

Answer 22

Use a damp blue litmus paper & place it in chlorine gas. If it turns white, then chlorine gas is present

Question 23

Why might the blue litmus paper momentarily turn red then white in a Chlorine test?

Answer 23

The solution of Chlorine is acidic & litmus paper turns red in acidic solutions

Question 24

Describe the pattern in reactivity of the Alkali metals

Answer 24

As you go down Group 7, the reactivity DECREASES

Question 25

The easier it is for a halogen to attract an electron...

Answer 25

...the more reactive the halogen will be

Question 26

What is **Atomic Radius**?

Answer 26

A measure of the size of atoms The distance from the nucleus to the outermost shell

Question 27

Explain **Group 7's** pattern of reactivity in terms of *electronic configurations*:

Answer 27

As you go down group 7, the atomic radius gets bigger therefore halogens become less reactive. This is because it gets harder to attract the extra electron to fill the outer shell when its further away

Question 28

What is a **Metal Halide**?

Answer 28

A salt/compound that forms between a metal & a halogen | e.g. Potassium Chloride

Question 29

What is a **Hydrogen Halide**?

Answer 29

A soluble compound that forms between a hydrogen and a halogen They can dissolve in water to form acidic solutions | e.g. Hydrogen Chloride

Question 30

List some properties of **Hydrogen Halides**:

Answer 30

* Acidic * Poisonous * Soluble in water

Question 31

What are some uses of Halide salts?

Answer 31

Sodium halide salts examples: * Table Salts - Sodium Chloride * Swimming pool disinfectant - Sodium Bromide * Toothpaste ingredient - Sodium Fluoride

Question 32

What is a **Displacement reaction**?

Answer 32

A reaction where a more reactive element replaces a less reactive element in a compound

Question 33

What is a **Redox reaction**?

Answer 33

A reaction where one substance is reduced and another is oxidised

Question 34

What will happen if you mix a *more reactive halogen* with a *less reactive halogen* from an aqueous solution?

Answer 34

The more reactive halogen can displace the less reactive halogen e.g. Chlorine is more reactive than bromine. So Chlorine will displace Bromine from an aqueous solution of its salt. Chlorine + Potassium Bromide ---> Bromine + Potassium Chloride

Question 35

What are some uses of **Halogens** & why?

Answer 35

* Disinfectants * Bleaches As they can kill microorganisms & remove colour from materials

Question 37

How do you determine the reactivity of Halogens?

Answer 37

By heating iron wool

Question 38

Using this table, predict the reactions of Astatine: | Astatine is placed below iodine in Group 7

Answer 38

Astatine should react very slowly with hydrogen, even when heated. A little hydrogen astatide should form, which should dissolve in water to form an acidic solution.

Question 39

What is **Group 0** also known as?

Answer 39

Noble gases

Question 40

Why are **Noble gases** unreactive?

Answer 40

They have a full/complete outer shell of electrons ---> Atoms create new bonds by losing, sharing or gaining electrons but noble gases already have a full outer shell. ---> There is no need for them to bond with other elements to achieve what they already have.

Question 41

What are some physical properties of **The Noble Gases** that are unique?

Answer 41

* Colourless * Low melting/boiling points * Poor conductors of heat/electricity * Inert

Question 42

What does **Inert** mean?

Answer 42

Does not react

Question 43

Explain the uses of **Krypton**? | Krypton is a type of Noble Gas

Answer 43

Used in **Photography** & **Lighting** It produces a bright white light when electricity is passes through it

Question 44

Explain the uses of **Argon**? | Argon is a type of Noble Gas

Answer 44

Used to **Prevent the oxidation of wine** As Its denser than air, Its added to the space above the wine in wine barrels

Question 45

Explain the uses of **Helium**? | Helium is a type of Noble Gas

Answer 45

Used in **Weather balloons** & **Airships** Helium has a low density and is non-flammable

Question 46

Explain the uses of **Neon**? | Neon is a type of Noble Gas

Answer 46

Used in **illuminated signs** Red-orange light produced when electricity is passed through it

Question 47

Describe the pattern in reactivity of the **Noble gases**

Answer 47

As you go DOWN the group, the boiling point & Density INCREASES