Covalent Bonding & Halogens Flashcards
(22 cards)
What is covalent bonding?
The sharing of electron pairs between non-metal atoms.
What type of elements form covalent bonds?
Non-metals only.
What is a molecule?
A group of atoms
What is a single covalent bond?
One shared pair of electrons.
Do simple covalent molecules conduct electricity? Why?
No – they don’t have free electrons or ions.
What is a giant covalent structure?
A large network of atoms all covalently bonded (e.g. diamond, graphite).
Why does diamond have a high melting point?
Strong covalent bonds throughout the structure require lots of energy to break.
How many bonds does carbon form in diamond?
Four covalent bonds.
Why can graphite conduct electricity?
It has delocalised electrons that can move.
What is graphene?
A single layer of graphite; one atom thick.
What are the halogens?
Group 7 non-metals: Fluorine, Chlorine, Bromine, Iodine, Astatine.
What is the reactivity trend of the halogens?
Reactivity decreases down the group.
Why do halogens become less reactive down the group?
It’s harder to gain an electron due to more shielding and greater distance from the nucleus.
What type of bonding do halogens form with metals?
Ionic bonding (they form -1 ions).
What type of bonding do halogens form with other non-metals?
Covalent bonding.
What colour is chlorine gas?
Pale green.
Why do simple molecular substances have low boiling points?
They have weak intermolecular forces that require little energy to overcome.
Why do giant covalent structures have high boiling points?
They have many strong covalent bonds that need a lot of energy to break.
What is the trend in reactivity of the halogens (Group 7) as you go down the group?
Reactivity decreases as you go down the group.
What is a halogen?
A halogen is a group 7 element in the periodic table, consisting of:
Fluorine (F)
Chlorine (Cl)
Bromine (Br)
Iodine (I)
Astatine (At)
They are non-metals and are known for being very reactive, especially with metals to form salts.
What is a halide?
A halide is a compound formed when a halogen combines with a metal or a non-metal. It is a salt containing a halogen ion (e.g., Cl⁻, Br⁻, I⁻).
Examples:
Sodium chloride (NaCl): Formed when sodium reacts with chlorine.
Potassium bromide (KBr): Formed when potassium reacts with bromine.
What is the trend in displacement reactions involving halogens?
The more reactive halogen will always displace the less reactive one.
Reactivity trend (most to least reactive): Fluorine > Chlorine > Bromine > Iodine.
