Groups in the periodic table Flashcards
Group 1 metals are known as what?
The Alkali metals.
What are the alkali metals?
Lithium, sodium, potassium rubidium, caesium and francium.
How many outer electrons do the alkali metals have?
1.
What are the properties of alkali metals?
- Very soft
- Low melting points and boiling points
What compounds do alkali metals form and why?
Ionic because they lose their outer electron so easily that sharing it to form a covalent is out of the question.
Complete the sentence: the more readily a metal loses its outer electrons…
The more reactive it is.
How does lithium react with cold water?
Lithium will move around the surface, fizzing furiously.
How do sodium and potassium react with cold water?
They will move around the surface, fizzing, and melt in the heat of the reaction. Potassium even gets hot enough to ignite the hydrogen gas produced.
What are the products of reacting alkali metals with water?
Hydroxide and hydrogen gas.
What is the reactivity trend in Group 1?
The elements get more reactive as you go down the group because the outer electron is lost more easily as it becomes further away from the nucleus as you go down.
Group 7 elements are known as what?
The Halogens.
The group 7 elements have how many electrons in there outer shell?
7.
What is a diatomic molecule?
They share one pair of electrons in a covalent bond, giving both atoms a full outer shell. e.g. Cl₂, Br₂, I₂.
What does chlorine look like at room temperature?
A green gas.
What does bromine look like at room temperature?
Red-brown liquid, which gives off an orange vapour.
What does iodine look like at room temperature?
A dark grey crystalline solid, which gives off a purple vapour.
What happens to the melting/boiling points as you go down Group 7?
As you go down Group 7 the melting points and boiling points of the halogens increase.
What is the chemical test for chlorine?
Hold a piece of damp blue litmus paper over it. Chlorine will bleach the litmus paper, turning it white. It may turn red for a moment, that’s because chlorine is acidic.
What is the reactivity trend for halogens?
The reactivity goes decreases as you go down the Group as the outer electron becomes harder to attract to fill the outer shell because it is further away from the nucleus.
Halogens can react with hydrogen to form what?
Hydrogen halides, which are soluble and form acidic solutions.
Halogens react with metals to form salts called what?
Metal halides.
What is a displacement reaction?
This is where a more reactive element `pushes out’ (displaces) a less reactive element from a compound.
The halogen displacement reactions are called what and why?
Redox reactions: The halogens gain electrons (reduction) whilst halide ions lose electrons (oxidation).
In a redox reaction, which substance is reduced?
Halogens.
In a redox reaction, which substance is oxidised
Halide ions.
How can you use displacement reactions to find the reactivity trend?
- Start with a small amount of halide salt solution in a test tube
- Add a few drops of a halogen solution, shake tube
- If there is a colour change, then a reaction has happened. The halogens has displaced the halide ions from the salt.
- If there is no colour change then there has been no reaction. The halogen is less reactive then the halide and so can’t displace it
Group 0 elements are called what?
The noble gases.
Group 0 is made up of what elements?
Helium, neon, argon, krypton, xenon and radon.
What are Group 0 elements at room temperature?
Colourless.
What does monatomic mean?
Made up of single atoms.
What does inert mean?
They don’t react.
Why are the Group 0 elements inert?
They have a full outer shell.
What are the uses of the noble gases?
- Provide an inert atmosphere
- Can be used in welding as it stops hot metals reacting with oxygen
- Helium is used in balloons as it has a lower density than air, so it can float
What happens to the boiling point, melting point and density of the Group 0 elements as you go down the group?
They all increase.
