| why does graphite conduct electricity? | only 3 of the outer electrons are used to form covalent bonds
there are delocalised electrons which allow it to conduct electricity |
| What elements take part in covalent bonding? | non-metal elements |
| how is a covalent bond forms | when two positive nuclei are held together by their common attraction for a shared pair of electrons |
| what is a single covalent bond? | a covalent bond consisting of one shared pair of electrons |
| what is a double covalent bond? | a covalent bond consisting of two shared pairs of electorns |
| what is a triple covalent bond? | a covalent bond consisting of three shared pairs of electrons |
| What are the seven diatomic elements? | hydrogen
nitrogen
oxygen
fluorine
chlorine
bromine
iodine |
| what is this molecule shape called? | linear |
| what is this molecule shape called? | angular |
| what is this molecule shape called? | trigonal pyramidal |
| what is this molecule shape called? | tetrahedral |
| what shape does water have? | angular |
| what shape does ammonia have? | trigonal pyramidal |
| What shape does hydrogen chloride have? | linear |
| what shape does methane have? | tetrahedral |
| what are the two types of covalent substances | discrete molecular and giant network |
| do covalent molecular substances have high or low melting and boiling points | low |
| why do covalent molecular substances have a low melting and boiling point | it requires little energy to break the weak van der waals forces of attraction between the molecules |
| do covalent network substances have a low or high melting and boiling point | high |
| why do covalent network substances have a high melting and boiling point? | it requires a lot of energy to break the strong covalent bonds between the molecules |
| do covalent substances conduct in any state? | no |
| why don't covalent substances conduct in any state? | there are no charged particles that are free to carry the current |
| is this a covalent molecular or network substance? | network |
| is this a covalent molecular or network substance? | molecular |
| what does a covalent network consist of ? | a giant 3 dimensional network of atoms joined by strong covalent bonds |
| what type of substance is diamond? | covalent network |
| what type of substance is graphite? | covalent network |
| what element is diamond made up of? | carbon |
| what element is graphite made up of? | carbon |
| does diamond conduct electricity? | no |
| why doesn't diamond conduct electricity? | all four outer electrons in each carbon atom are used to form covalent bonds |
| does graphite conduct electricity? | yes |
| why does graphite conduct electricity? | only 3 of the outer electrons are used to form covalent bonds
there are delocalised electrons which allow it to conduct electricity |
| what is a delocalised electron? | electrons that can move |
| are covalent molecular substances soluble? | some molecular substances are soluble in water and others are soluble in other solvents like ethanol and acetone |
| are covalent network substances soluble? | no
not in any solvents |
| what is the relationship between the group of a molecule's central atom and its shape? | in angular, trigonal pyramidal and tetrahedral molecules, if central atoms have the same group the molecule will have the same shape |
