Halogens Flashcards
What group is called the halogens
Group 7
Give the name of Group 7
Halogens
Give the formula for each halogen
Fluorine - F2
Chlorine - Cl2
Bromine - Br2
Iodine - I2 (subscript 2)
What type of structure are the halogens
Halogens are molecular in structure
State some physical properties of the Group 7 elements
low density
brittle
thermal insulator
electrical insulator
dull
What does aqueous mean
Aqueous means dissolved in water
What are group 7 ions called
Group 7 ions are called halide ions
Finish the sentence:
A more reactive halogen will displace a less reactive halide ion from it’s _________ compound
A more reactive halogen will displace a less reactive halide ion from it’s ionic compound
What colour are halide ion compounds
Halide ion compounds are colourless
e.g. potassium chloride
What colour are halide ion compounds
Halide ion compounds are colourless
e.g. potassium chloride
State the properties of Fluorine
Fluorine is a pale, yellow gas, poisonous and highly reactive
State the properties of Chlorine
Chlorine is denser than fluorine
Chlorine is a dense green gas
It is very reactive (but less reactive than fluorine)
Poisonous
State the properties of Bromine
Bromine is a dense, poisonous, orange-brown volatile liquid
Volatile- it can change state easily
Bromine easily turns into a vapour
State the properties of Iodine
Iodine is a dark grey solid. Iodine sublimes to a purple vapour upon heating
Subliming - when a solid turns into a vapour or vice versa
All halogens form ___ vapours
All halogens form coloured vapours
Describe and explain halogens in terms of melting points and boiling points
Halogens have low melting points and boiling points as the forces between the molecules are very weak.
In their elemental form, what are halogens
In their elemental form, all halogens are diatomic
Describe the trend in melting points in group 7
In group 7 Their melting points increase, down the group
Describe the trend in boiling points in group 7
In Group 7, their boiling points increase, down the group
Describe the trend in reactivity in Group 7
In Group 7, their reactivity decreases, down the group
What are diatomic molecules
Diatomic molecules are two atoms that are covalently bonded together
Explain the trend in melting point and boiling point in Group 7
The melting points and boiling points increase down the group, because as going down Group 7 the molecules become larger, the intermolecular forces become stronger, meaning more energy is need to overcome these forces.
In terms of electrons, what happens to Group 7 atoms when they react with metals
What type of compound is formed
When Group 7 atoms react with metals, they gain an extra electron, from the metal to form 1- ions
An ionic compound is formed
In terms of electrons, what happens to Group 7 atoms when they react with non-metals
What type of compound is formed
Group 7 atoms share their electrons with another atom
A covalent/simple molecular/molecular compound is formed
What colour is bromine water Br2 (aq) - (bromine dissolved in water
Bromine water is orange/yellow
What colour is chlorine water Cl2 (aq) - (chlorine dissolved in water
Chlorine water is pale green
What colour is iodine water I2 (aq) - (iodine dissolved in water
Iodine water is brown
State the products and an observation from the following reaction
Potassium bromide + chlorine
Potassium bromide + chlorine —> potassium chloride + bromine
An orange/yellow solution forms - this is the colour of the displaced bromine dissolved in water
State the products and an observation from the following reaction
Potassium iodide + chlorine
Potassium iodide + chlorine ——> potassium chloride + iodine
A brown solution forms - this is the colour of the displaced iodine dissolved in water
Explain the trend in reactivity of Group 7
Going down the group, the atoms become larger
The distance between the nucleus and the outer electron is greater, meaning it has more electron shells.
This results in increased shielding, which means the electrostatic attraction between the nucleus and the outer electron is weaker
Therefore, it is harder to attract and gain an extra incoming electron
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32
Q
Why is sodium more reactive than lithium
A
A sodium atom is larger than a lithium atom
This means that the distance between sodium’s nucleus and it’s outer electron is greater than the distance between lithium’s nucleus and outer electron, which means that sodium has more electron shells than lithium.
This results in more shielding being experienced by sodium than lithium , which means that the electrostatic attraction between sodium’s nucleus and outer electron is weaker than the attraction between lithium’s nucleus and outer electron,
Therefore, sodium’s outer electron is lost more easily
Why is fluorine more reactive than bromine
Both Fluorine and Bromine atoms need to gain an electron to achieve a full outer shell
Due to the fact Fluorine is smaller than Bromine, the distance between Fluorine’s nucleus and it’s outer electron is less than the distance between bromines nucleus and outer electron, which means that fluorine has less electron shells than lithium.
This results in less shielding being experienced by fluorine than bromine, which means that the electrostatic attraction between fluorine’s nucleus and outer electron is stronger than the attraction between bromine’s nucleus and outer electron,
Therefore, fluorine gains an electron easier than bromine so it is more reactive
Draw a fluorine atom
