C7 types of substances

Question 1

Explain the properties of ionic compounds.

Answer 1

● Ionic compounds are made up of a metal and a nonmetal
● Ionic compounds have regular structures (giant ionic lattices) in which there are
strong electrostatic forces of attraction in all directions between oppositely
charged ions.
● They have high melting and boiling points, because a lot of energy is required to
break the many strong bonds.
● When melted or dissolved in water, ionic compounds conduct electricity because
the ions are free to move and carry current, and they do not conduct electricity
as solids, because the ions are fixed and are not able to move, carrying charge
with them.
● Often dissolve in water to form an aqueous solution

Question 2

what are the properties of simple covalent bonding?

Answer 2

Substances that consist of small molecules are usually gases or liquids that have
low boiling and melting points. They are made up of nonmetal elements.
● Substances that consist of small molecules have weak intermolecular forces
between the molecules. These are broken in boiling or melting, not the covalent
bonds.
○ The intermolecular forces increase with the size of the molecules, so
larger molecules have higher melting and boiling points.
● Substances that consist of small molecules don’t conduct electricity, because
small molecules do not have an overall electric charge. although, some
breakdown in water to form ions which can conduct electricity
● Many are insoluble in water, but some are soluble because they can form
intermolecular forces with water which are stronger than those between water
molecules or their own molecules already (e.g. CO2 and NH3 are soluble)

Question 3

what are the properties of giant covalent structures?

Answer 3

They are made up of nonmetal elements
● Substances that consist of giant covalent structures are solids with very high
melting points.
o All of the atoms in these structures are linked to other atoms by strong
covalent bonds.
▪ These bonds must be overcome to melt or boil these substances.
● some giant covalent structures can conduct electricity, whereas others can’t

Question 4

what are the properties of metals?

Answer 4

Properties of metals
● Metals consist of giant structures of atoms arranged in a regular pattern. They
are always made up of just metallic elements
● The electrons in the outer shell of metal atoms are delocalised and so are free to
move through the whole structure.
● The sharing of delocalised electrons gives rise to strong metallic bonds.
● Metals have giant structures of atoms with strong metallic bonding.
o Therefore, most metals have high melting and boiling points.
o They can conduct heat and electricity because of the delocalised
electrons in their structures.
o Conduction depends on the ability for electrons to move throughout the
metal.
o The layers of atoms in metals are able to slide over each other, so metals
can be bent and shaped.
o insoluble in water- but some will react with it instead

Question 5

describe the properties of graphene in terms of it’s bonding.

Answer 5

it is soft and slippery due to the layers of covalent bonds with weak intermolecular forces in between that are easily broken

Question 6

what is a delocalised electron and what does it do?

Answer 6

A delocalized electron is an electron in a molecule, ion, or solid metal that isn’t tied to a single atom or covalent bond