The halogens are the non-metal elements in Group 7 of the periodic table: fluorine , chlorine , bromine , iodine and astatine . They are all poisonous , diatomic molecules, and each has seven electrons in its outer shell.

Complete the table of Group 7 halogen properties. Halogen State at room temperature Colour Fluorine Chlorine Bromine Iodine

Complete the table of Group 7 halogen properties. Halogen State at room temperature Colour Fluorine Gas Yellow Chlorine Gas Pale yellow-green Bromine Liquid Red-brown Iodine Solid Grey

Why do melting and boiling points increase as you go down Group 7?

Melting and boiling points increase as you go down Group 7 because the atoms become larger , which strengthens the intermolecular forces between molecules. More energy is needed to overcome these forces, so higher temperatures are required to melt or boil the halogen.

True or False? All halogens are diatomic molecules.

True. All halogens exist as diatomic molecules, meaning each molecule contains two halogen atoms joined by a single covalent bond . For example, chlorine exists as Cl 2 .

What type of compounds do halogens form when they react with metals?

When halogens react with metals, they form ionic compounds called metal halide salts . The halide ion carries a -1 charge , so the number of halogen atoms in the compound depends on the valency of the metal.

A halogen .......... reaction occurs when a more reactive halogen displaces a less reactive halogen from an aqueous solution of its .......... .

A halogen displacement reaction occurs when a more reactive halogen displaces a less reactive halogen from an aqueous solution of its halide .

What colour change is observed when chlorine solution is added to potassium bromide solution?

When chlorine solution is added to potassium bromide solution, the solution turns orange as bromine is produced. Chlorine is more reactive than bromine and displaces bromine from the potassium bromide solution.

True or False? Bromine can displace chlorine from a solution of potassium chloride.

False. Bromine is less reactive than chlorine, so it cannot displace chlorine. Only a more reactive halogen can displace a less reactive one from a solution of its halide. Chlorine would displace bromine, not the other way around.

What is a displacement reaction in the context of Group 7?

A displacement reaction is when a more reactive halogen pushes out a less reactive halogen from an aqueous solution of its halide salt . Reactivity decreases down Group 7, so chlorine can displace bromine or iodine, and bromine can displace iodine.

What is a halide ion ?

A halide ion is formed when a halogen atom gains one electron to achieve a full outer shell. Halide ions carry a -1 charge and are named by changing the halogen's suffix to "-ide" (e.g., chloride , bromide , iodide ).

Why does reactivity decrease as you go down Group 7?

Reactivity decreases because as you go down Group 7, the outer shell gets further from the nucleus , so the force of attraction for an incoming electron becomes weaker. This makes it harder for atoms to gain an electron, reducing reactivity.

True or False? Fluorine is the most reactive halogen because its outer shell is closest to the nucleus.

True. Fluorine is the smallest halogen, so its outer shell is the closest to the nucleus of all the halogens. This means the nucleus can attract electrons most strongly, making fluorine the most reactive halogen.

Halogens become .......... reactive as you go down Group 7, because the outer shell gets further from the .......... and the attractive force decreases.

Halogens become less reactive as you go down Group 7, because the outer shell gets further from the nucleus and the attractive force decreases.

What type of ion is formed when a halogen reacts, and what charge does it carry?

When a halogen reacts, it gains one electron to form a halide ion with a -1 charge . This gives the halogen a full outer shell, achieving noble gas configuration.

True or False? Iodine is more reactive than chlorine in Group 7.

False. Iodine is less reactive than chlorine. Iodine is further down Group 7, so its outer shell is further from the nucleus. The attractive force for gaining an electron is weaker in iodine, making it less reactive than chlorine.

IGCSEChemistryEdexcelChemistry (Modular)Unit 2Flashcards6. Inorganic Chemistry: Part 2Group 7 (halogens)

Group 7 (halogens) (Edexcel IGCSE Chemistry (Modular): Unit 2): Flashcards

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FrontGroup 7 (Halogens)
What are halogens?

Halogen	State at room temperature	Colour
Fluorine	Gas	Yellow
Chlorine	Gas	Pale yellow-green
Bromine	Liquid	Red-brown
Iodine	Solid	Grey

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Cards in this collection (15)

What are halogens?
The halogens are the non-metal elements in Group 7 of the periodic table: fluorine, chlorine, bromine, iodine and astatine. They are all poisonous, diatomic molecules, and each has seven electrons in its outer shell.
Complete the table of Group 7 halogen properties.
Halogen
State at room temperature
Colour
Fluorine
Chlorine
Bromine
Iodine
Complete the table of Group 7 halogen properties.
Halogen
State at room temperature
Colour
Fluorine
Gas
Yellow
Chlorine
Gas
Pale yellow-green
Bromine
Liquid
Red-brown
Iodine
Solid
Grey
Why do melting and boiling points increase as you go down Group 7?
Melting and boiling points increase as you go down Group 7 because the atoms become larger, which strengthens the intermolecular forces between molecules. More energy is needed to overcome these forces, so higher temperatures are required to melt or boil the halogen.
True or False?
All halogens are diatomic molecules.
True.
All halogens exist as diatomic molecules, meaning each molecule contains two halogen atoms joined by a single covalent bond. For example, chlorine exists as Cl₂.
What type of compounds do halogens form when they react with metals?
When halogens react with metals, they form ionic compounds called metal halide salts. The halide ion carries a -1 charge, so the number of halogen atoms in the compound depends on the valency of the metal.
A halogen .......... reaction occurs when a more reactive halogen displaces a less reactive halogen from an aqueous solution of its .......... .
A halogen displacement reaction occurs when a more reactive halogen displaces a less reactive halogen from an aqueous solution of its halide.
What colour change is observed when chlorine solution is added to potassium bromide solution?
When chlorine solution is added to potassium bromide solution, the solution turns orange as bromine is produced. Chlorine is more reactive than bromine and displaces bromine from the potassium bromide solution.
True or False?
Bromine can displace chlorine from a solution of potassium chloride.
False.
Bromine is less reactive than chlorine, so it cannot displace chlorine. Only a more reactive halogen can displace a less reactive one from a solution of its halide. Chlorine would displace bromine, not the other way around.
What is a displacement reaction in the context of Group 7?
A displacement reaction is when a more reactive halogen pushes out a less reactive halogen from an aqueous solution of its halide salt. Reactivity decreases down Group 7, so chlorine can displace bromine or iodine, and bromine can displace iodine.
What is a halide ion?
A halide ion is formed when a halogen atom gains one electron to achieve a full outer shell. Halide ions carry a -1 charge and are named by changing the halogen's suffix to "-ide" (e.g., chloride, bromide, iodide).
Why does reactivity decrease as you go down Group 7?
Reactivity decreases because as you go down Group 7, the outer shell gets further from the nucleus, so the force of attraction for an incoming electron becomes weaker. This makes it harder for atoms to gain an electron, reducing reactivity.
True or False?
Fluorine is the most reactive halogen because its outer shell is closest to the nucleus.
True.
Fluorine is the smallest halogen, so its outer shell is the closest to the nucleus of all the halogens. This means the nucleus can attract electrons most strongly, making fluorine the most reactive halogen.
Halogens become .......... reactive as you go down Group 7, because the outer shell gets further from the .......... and the attractive force decreases.
Halogens become less reactive as you go down Group 7, because the outer shell gets further from the nucleus and the attractive force decreases.
What type of ion is formed when a halogen reacts, and what charge does it carry?
When a halogen reacts, it gains one electron to form a halide ion with a -1 charge. This gives the halogen a full outer shell, achieving noble gas configuration.
True or False?
Iodine is more reactive than chlorine in Group 7.
False.
Iodine is less reactive than chlorine. Iodine is further down Group 7, so its outer shell is further from the nucleus. The attractive force for gaining an electron is weaker in iodine, making it less reactive than chlorine.

Halogen	State at room temperature	Colour
Fluorine	Gas	Yellow
Chlorine	Gas	Pale yellow-green
Bromine	Liquid	Red-brown
Iodine	Solid	Grey

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