17 - Groups in the Periodic Table Flashcards
What is group 1 in the periodic table also known as?
Alkali Metals
Give some examples of Group 1 elements:
- Hydrogen
- Lithium
- Sodium
- Potassium
- Rubidium
- Caesium
- Francium
Where do Alkali Metals need to be stored?
In oil
What are some physical properties of Alkali metals that are unique?
- Soft
- Low melting points
- Low densities
What’s the general equation for an alkali metal reacting with water?
Alkali metal + water —> metal hydroxide + hydrogen
Describe the reaction of lithium & water?
Bubbles fiercely on the surface
Describe the reaction of sodium & water?
Melts into a ball & fizzes about on the surface
Describe the reaction of potassium & water?
Bursts into flames & flies about the surface
Describe the pattern in reactivity of the alkali metals
Reactivity of Group 1 elements INCREASES as you go down the group
Describe the electronic configuration of all alkali metals:
- One electron in outer shell
—> Gives similar chemical properties
The more readily a metal loses its outer electrons…
…The more reactive it is
Explain Group 1’s pattern of reactivity in terms of electronic
configurations:
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
How can you predict the reactions of the group 1 elements?
And can you give an example?
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
What is Group 7 in the periodic table also known as?
The Halogens
Give some examples of Group 7 elements:
- Fluorine
- Chlorine
- Bromine
- Iodine
- Astatine
- Tennessine
What are some physical properties of The Halogens that are unique?
- 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
Why does the melting/boiling points of Halogens/Noble gases INCREASE as you go down the group?
- The Molecules become larger
- Intermolecular forces become stronger
—> More energy is needed to overcome these forces
What is the colour & the physical state of Chlorine at room temperature?
- Pale green
- Gas
What is the colour & the physical state of Bromine at room temperature?
- Brown
- Liquid
- Gives off an orange vapour
What is the colour & the physical state of Iodine at room temperature?
- Purple-Black
- Solid
- Gives off a purple vapour (when heated)
How can you predict the reactions of the group 7 elements?
And can you give an example?
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
How would you test for Chlorine?
Use a damp blue litmus paper & place it in chlorine gas. If it turns white, then chlorine gas is present
Why might the blue litmus paper momentarily turn red then white in a Chlorine test?
The solution of Chlorine is acidic & litmus paper turns red in acidic solutions
Describe the pattern in reactivity of the Alkali metals
As you go down Group 7, the reactivity DECREASES
The easier it is for a halogen to attract an electron…
…the more reactive the halogen will be
What is Atomic Radius?
A measure of the size of atoms
The distance from the nucleus to the outermost shell
Explain Group 7’s pattern of reactivity in terms of electronic
configurations:
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
What is a Metal Halide?
A salt/compound that forms between a metal & a halogen
e.g. Potassium Chloride
What is a Hydrogen Halide?
A soluble compound that forms between a hydrogen and a halogen
They can dissolve in water to form acidic solutions
e.g. Hydrogen Chloride
List some properties of Hydrogen Halides:
- Acidic
- Poisonous
- Soluble in water
What are some uses of Halide salts?
Sodium halide salts examples:
* Table Salts - Sodium Chloride
* Swimming pool disinfectant - Sodium Bromide
* Toothpaste ingredient - Sodium Fluoride
What is a Displacement reaction?
A reaction where a more reactive element replaces a less reactive element in a compound
What is a Redox reaction?
A reaction where one substance is reduced and another is oxidised
What will happen if you mix a more reactive halogen with a less reactive halogen from an aqueous solution?
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
What are some uses of Halogens & why?
- Disinfectants
- Bleaches
As they can kill microorganisms & remove colour from materials
How do you determine the reactivity of Halogens?
By heating iron wool
Using this table, predict the reactions of Astatine:
Astatine is placed below iodine in Group 7
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.
What is Group 0 also known as?
Noble gases
Why are Noble gases unreactive?
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.
What are some physical properties of The Noble Gases that are unique?
- Colourless
- Low melting/boiling points
- Poor conductors of heat/electricity
- Inert
What does Inert mean?
Does not react
Explain the uses of Krypton?
Krypton is a type of Noble Gas
Used in Photography & Lighting
It produces a bright white light when electricity is passes through it
Explain the uses of Argon?
Argon is a type of Noble Gas
Used to Prevent the oxidation of wine
As Its denser than air, Its added to the space above the wine in wine barrels
Explain the uses of Helium?
Helium is a type of Noble Gas
Used in Weather balloons & Airships
Helium has a low density and is non-flammable
Explain the uses of Neon?
Neon is a type of Noble Gas
Used in illuminated signs
Red-orange light produced when electricity is passed through it
Describe the pattern in reactivity of the Noble gases
As you go DOWN the group, the boiling point & Density INCREASES
