SC5+6+7 Flashcards
(21 cards)
What is ionic bonding?
Metal + non-metal transferring electrons to form oppositely charged ions.
What structure do ionic compounds form?
Giant ionic lattice (regular arrangement of + and - ions)
Why do ionic compounds have high melting points?
Strong electrostatic forces between ions require lots of energy to break
Why are ionic compounds brittle?
Layers shift, causing like charges to repel and break the lattice
Why do ionic compounds conduct when molten/dissolved?
Ions are free to move and carry charge
How many bonds do O/N/C typically form?
O: 2, N: 3, C: 4
What is covalent bonding?
Non-metals sharing pairs of electrons
What is a dative covalent bond?
One atom provides both shared electrons (e.g., NH₄⁺)
Why do simple molecules (e.g., H₂O) have low boiling points?
Weak intermolecular forces between molecules (not bonds)
What state are small covalent molecules at room temp?
Gas/liquid (e.g., CO₂, H₂O)
Compare diamond and graphite:
Diamond: 4 bonds per carbon, rigid, doesn’t conduct.
Graphite: 3 bonds, layers slide, conducts (delocalised electrons)
What is graphene?
Single layer of graphite; strong and conductive
What is metallic bonding?
Positive metal ions in a “sea” of delocalised electrons
Why are metals malleable?
Layers of ions can slide without breaking bonds
Why do metals conduct?
Delocalised electrons carry charge
Why do giant covalent structures (e.g., SiO₂) have high melting points?
Many strong covalent bonds must be broken
Ionic vs. Covalent:
Ionic: Metal + non-metal, conducts when molten.
Covalent: Non-metals only, simple molecules don’t conduct
Graphite vs. Metals:
Both conduct, but graphite has layered covalent bonds; metals have metallic bonding
What is a delocalised electron?
an electron in an atom, ion, or molecule that is not connected to a single atom or covalent bond
What is an allotrope?
different forms of the same element
What is a polymer?
a large molecule formed from many identical smaller molecules known as monomers
