Group 7 Flashcards
Describe the trend in atomic radius as you go down group 7
Increases There are more shells
Describe how the ionic radius compared to the atomic radius in group 7
The halide ion (X-) has the same number of protons as the halogen atom (X) but more electrons so the attraction is weaker.
Describe the trend in boiling point as you go down group 7
Increases The molecules are larger and have more electrons. This makes the Van Der Waals forces between the molecules are stronger and more energy is needed to overcome them.
Describe the trend in volatility down group 7
Less volatile The molecules are larger and have more electrons. This makes the Van Der Waals forces between the molecules are stronger and more energy is needed to overcome them.
Describe the trend in electronegativity as you go down group 7
Decreases Shielding increases and so the attraction is weaker therefore the nuclear attraction to the shared pair of electrons is weaker
Describe the trend in first ionisation energy down group 7
Decreases Shielding increases as there are more shells therefore the nuclear attraction to the outer electron is less and less energy is needed to remove it
What is the colour of, state at room temperature of, colour of the aqueous solution of and the colour in cyclohexane of Cl2.
Colour: green State at room temp: gas Colour of aqueous sol: pale green Colour in cyclohexane: pale green
What is the colour of, state at room temperature of, colour of the aqueous solution of and the colour in cyclohexane of Br2.
Colour: Red-brown State at room temp: liquid Colour of aqueous sol: orange Colour in cyclohexane: orange
What is the colour of, state at room temperature of, colour of the aqueous solution of and the colour in cyclohexane of I2
Colour: black State at room temp: solid Colour of aqueous sol: brown Colour in cyclohexane: purple
Why are the halogens more soluble in non-polar solvents?
They are non-polar
Describe the trend in solubility in water as you go down group 7
Decreases The halogen becomes larger
What are the results of the experiment that provides evidence for the trend in oxidising powers of the halogens?
What is the full equation, ionic equaion and half equations for the equation between chlorine and potassium bromide.
What is the full equation, ionic equaion and half equations for the equation between bromine and potassium iodide.
What is the full equation, ionic equaion and half equations for the equation between chlorine and potassium iodide.
Are halogens oxidising agents or reducing agents? Why?
Oxidising agents
They gain electrons to fro halide ions
What is the general equation for the oxidation of a halogen?
Describe the trend in the ability of the halogens to act as oxidising agents down group 7
Decreases
More shielding due to an increase in the number of shells
Therefore the ability to gain electrons is less as the nuclear attraction decreases.
Are halides oxidising or reducing agents?
Reducing
What are the possible reduction products of H2SO4 when it is reduced by a halide? Give the oxidation numbers and the appearence/test of the product.
- Sulfuric (VI) acid, +6
- Sulfur dioxide, +4, Turns orange dichromate paper green + choking smell
- Sulfur, 0, yellow solid
- H2S, -2, Turns leadethanoate paper black + smells of bad eggs
What is the general equation for the oxidation of a halide ion?
Describe the method of using halide ions to reduce H2SO4
- Put 0.1g of the solid halide compound in a test tube
- Add 10 drops of concentrated H2SO4
- Warm is necessary
- Identify as many products as you can