molecular compounds

what is a compound

a substance that contains atoms of more than one element, chemically joined together by bonds

what type of bonds hold atoms together in a molecule?

strong covalent bonds

what are intermolecular forces?

weak forces of attraction between molecules

why do simple molecular structures have a low boiling point compared to giant covalent structures?

because only weak intermolecular forces need to be overcome, which requires little energy

what happens to intermolecular forces when water changes from liquid to gas

they are overcome, allowing water molecules to separate and become gas

what is an electric current?

a flow of charged particles

why cant simple molecules conduct electricity?

they have no overall charge and no free moving electrons or ions to carry a current

how do covalent bonds hold atoms together?

electrons are shared between two atoms, and strong forces between negatively charged electrons and positively charged nuclei keep them in place

why cant electrons in a covalent bond carry a current?

they are held in place by strong forces of attraction and cant flow freely

what are the properties of a typical covalent, simple molecular compound?

• low melting and boiling points

• poor conduction of electricity

what are monomers?

small, simple molecules that can be joined in a chain to form a polymer

how are monomers usually linked together?

by covalent bonds between carbon atoms

why can carbon atoms form lomg chains in polymers?

carbon atoms can form up to four covalent bonds with other atoms

how does polymer length affect its properties?

longer polymers have more intermolecular forces and tend to get tangled, leading to high melting and boiling points