C6: Groups In The Periodic Table Flashcards
How are elements arranged in the
periodic table?
- ordered in increasing atomic number
- groups have same number of outer shell electrons
- periods have same number of electron shells
How many electrons are in the outer shell of group 1?
One
Why do elements in the same group have similar chemical properties?
They have the same number of electrons in the outer shell
What group are the alkali metals?
Group 1
What are the 2 properties and 1 element of alkali metals?
- low melting points, soft
- react with water to form alkaline solutions
Why should alkali metals be stored in oil?
To prevent them reacting with water vapour and oxygen in the air
What group are the halogens in and why?
Group 7 because they have 7 outer shell electrons
What is the colour and state of chlorine at room temperature?
Pale green gas
What is the colour and state of bromine at room temperature?
Red-brown liquid
What is the colour and state of iodine at room temperature?
Black solid
What happens to halogens as you go down the group?
Melting and boiling point increases
Why does melting and boiling point increase down group 7?
Molecules get bigger down the group so there are more intermolecular forces to overcome during melting/ boiling so more energy is required
What is the chemical test for chlorine?
Damp litmus paper placed into a test tube of gas, if chlorine is present, the litmus paper will turn red them white due to the bleaching effect if chlorine
What is produced when a halogen reacts with a metal?
Metal halide salt
Describe the trend in reactivity of the halogens and how does this affect the rate of reaction?
- reactivity decreases down group 7
- rate of reaction decreases down group 7
What is formed when a hydrogen reacts with a halogen?
Hydrogen halides
When does a halogen displacement reaction occur?
When a more reactive halogen displaces a less reactive halogen from an aqueous solution to its halide
What colours are solutions of chlorine, bromine and iodine?
Chlorine water - colourless
Bromine water - orange
Iodine solution - brown
What is a redox reaction?
A reaction where oxidation and reduction take place at the same time
Bromine reacts with potassium iodide, what is reduced and what is oxidised?
- Bromine is reduced to bromide ions
- Iodide ions are oxidised to iodine
What is the name used to describe the elements in group 0 of the periodic table?
Noble gases
How many electrons do the noble gases have in their outer shell?
0, no incomplete shells of electrons
What properties of helium makes it suitable for use in balloons?
It is less dense than air and doesn’t burn
Why is argon used to fill electric light bulbs?
It is very chemically inert so will not react when the light bulb gets hot (non-flammable)
What is the trend in boiling points down group 0?
Boiling point increases down group 0 because the relative atomic mass increases so there are more intermolecular forces between atoms
What is the trend in density down group 0?
Density increases down the group, helium is the least dense and radon is the most dense
