Group 7 Flashcards
Group 7 elements
Fluorine
Chlorine
Bromine
Iodine
What state is fluorine at room temperature?
Gas
What colour is fluorine gas?
Pale yellow
Does fluorine dissolve in water?
No
Does fluorine dissolve in organic solvents eg hexane?
No
What state is chlorine at room temperature?
Gas
What colour is chlorine gas?
Green
Does chlorine dissolve in water?
Yes
What colour is chlorine dissolved in water?
Pale green to colourless
What colour is chlorine dissolved in hexane?
Virtually colourless
What state is bromine in at room temperature?
Liquid
Bromine liquid colour
Red-brown
Does bromine dissolve in water?
Yes
Bromine water colour
Yellow-orange
Does bromine dissolve in hexane?
Yes
Bromine dissolved in hexane colour
Orange-red
What state is iodine in at room temperature?
Solid
Iodine solid colour
Grey
Does iodine dissolve in water
Barely
What colour does iodine dissolved in water form?
A brown solution
Can iodine dissolve in iodine compound solvents (such as KI)?
Yes and forms a brown solution
What colour does iodine dissolved in ethanol form?
Yellow
What colour does iodine dissolved in hexane form?
Purple
Iodine gas colour
Purple
How does the reactivity of halogens change down the group?
Decreases
Why does the reactivity of halogens decrease down the group?
Because they react by gaining an electron to complete outer shell
Going down the group, the atomic radii increases so:
Outer electrons experience more shielding due to more internal electrons
Outer shell electrons are further from nucleus
So decreased electrostatic attraction between nucleus and reacting electron due to experiencing less nuclear force
(Overcomes increase in number of protons)
How does electro negativity of halogens change down the group?
Decreases down the group
Why does electronegativity of halogens decrease down the group?
Because electronegativity is ability to attract bonding pair of electrons to nucleus
Going down the group the atomic radii increases so the number of electrons shielding bonded pair of electrons from nuclear charge increases and bonding pair of electrons is at a further distance from nucleus
This decreases nuclear force thus EN decreases down the group
(Overcomes increasing proton number)
How does melting and boiling point change down the group?
Increases down the group
Why does the mp/bp increase down the group?
Because going down group 7, there is an increase in atomic radii thus more electrons per atom
So an increase in number of London forces formed between diatomic molecules
Therefore, more energy is needed to overcome these London forces to melt or boil
Why do halogens not react as easily with water?
Because water is a polar solvent that can form London forces, permanent dipole dipole forces AND hydrogen bonds
Halogen molecules are non polar thus do not dissolve as readily
Why do halogens dissolve easily with organic solvents eg hexane?
Because they are both non polar
Why is the ionic radii of halide ions larger than the atomic radii of its respective element?
Because halide ions have one more electron
Which increases repulsion
Which expands radii
