[7] Covalent bonding

What is a covalent bond?

a shared group of negative electrons electrostatically attracted to a positive nuclei

what is a covalent bond between

non metal and a non metal

Why are substances with simple molecular structures usually gases, liquids, or solids with low melting and boiling points?

Substances with simple molecular structures have weak intermolecular forces of attraction between the molecules. These forces are easily broken, so the substances have low melting and boiling points.

Why do substances with simple molecular structures have increasing melting and boiling points with increasing relative molecular mass?

As the relative molecular mass increases, the size of the molecules increases, which results in stronger intermolecular forces. This requires more energy to overcome, leading to higher melting and boiling points.

Why do substances with giant covalent structures have high melting and boiling points?

Substances with giant covalent structures have strong covalent bonds between atoms throughout the structure. A lot of energy is needed to break these strong bonds, resulting in high melting and boiling points.

Do covalent compounds conduct electricity?

no as they do not have delocalized electrons or ions to carry the electrical charge.

How do the structures of C₆₀ fullerene influence its physical properties?

60 carbon atoms form a spherical shape

Soft and brittle because weak intermolecular forces between individual molecules.

poor conductor of electricity as no delocalized electrons

How does the structure of diamond affect its properties?

Each carbon atom is bonded to four others in a giant covalent structure

High melting point as strong covalent bonds need a lot of energy to break.

Does not conduct electricity as no free electrons.

How does the structure of graphite affect its properties?

Each carbon atom is covalently bonded to three other carbon atoms, forming layers of hexagonal rings

Soft as the layers are held together by weak intermolecular forces so they slide over each other.

High melting point because strong covalent bonds within layers.

Conducts electricity as free electrons between layers can carry charge.