Ionic And Covalent Bonding

What is an allotrope?

Allotropes are different structural forms of the same element existing in the same physical state (like solid, liquid or gas) but with different arrangements of atoms, changing their chemical properties.

Why is Hardness a property of Diamond?

S: Macromolecular

B: Each C atom forms 4 strong covalent bonds

P: This takes a great deal of FORCE to break

Why is “High Melting Point” a property of Diamond?

S: Macromolecular

B: Each C atom forms 4 strong covalent bonds

P: This takes a great deal of ENERGY to break the bonds.

Why is “Doesn’t Conduct Electricity’ a property of Diamond?

No delocalised electrons can flow freely through the macromolecule, which carry charge. There are no delocalised electrons because each C atom forms 4 strong covalent bonds.

Why is Diamond Transparent?

Light can pass through the macromolecule because all atoms are being held in place by strong covalent bonds

Why is graphite CONDUCTIVE?

S: Macromolecular

B: Each C atom forms 3 strong covalent bonds, but there are weak forces between the layers holding them together.

P: There is one delocalised electron PER atom which is the electron not used in the covalent bond.

Why does graphite have a HMP (High melting point)

S: Macromolecular

B: Many strong covalent bonds per C atom

P: Takes a great deal of energy to break

Why is graphite soft?

S: Macromolecular WITH LAYERED HEXAGONS OF C ATOMS

B: Strong covalent bond between the atoms in the layers but weak forces between the layers.

P: These forces break easily and layers can slide over each other

Why is graphite conductive of electricity?

S: Macromolecular with layered hexagons

B: Each C atom forms only 3 covalent bonds so there is one delocalised electron per C atom.

P: There are many delocalised electrons carrying charge

What is a covalent bond?

a strong chemical link where two non-metal atoms share pairs of electrons to achieve stable outer electron shells

What is a fullerene?

A fullerene is an atom which has been arranged in spheres or tubes (hollow shapes)

Why are fullerenes soft and slippery?

There are weak forces between the tubes or spheres which break easily allowing them to slide past each other.

Why do fullerenes have a HMP?

In tubes or spheres the C atoms are held in place by strong covalent bonds which take a great deal of energy to break.

Why are fullerenes good conductors?

Each C atom forms 3 covalent bonds leaving many delocalised electrons to flow through carrying charge

Why are nanotubes long and thin?

Classified as a fibre and substances can flow down through it very easily.

What is an ionic bond?

a strong electrostatic attraction between oppositely charged ions that forms when one atom transfers one or more electrons to another