Covalent bonding Flashcards
What does covalent bonding occur between?
two non metals
what do the non metals want to do?
gain electrons
how do the non metals bond?
In order to bond together that cannot give and take electrons so they share instead.
How does the covalent bond form?
The covalent bond forms because the positive nucleus (contains protons) forms an electrostatic force which holds onto the shared pair of electrons.
How do you draw covalent bonds?
combine the outer shells
why do most small covalent molecules exist as gases?
There are very weak forces between the molecules. Only a small amount of energy causes the molecules to separate into gases
name some characteristics on covalent bonding
the bonds are strong
intermolecular forces are weak
small molecules have low melting point
giant covalent structures have strong bonds therefore a high melting point
name some examples of giant covalent structures
graphite
diamonds
fullerene
all allotropes (made of) carbon
name some characteristics of diamond
each carbon atom has four bonds these bonds are all strong and covalent there are lots of bonds so lots of energy is needed to break them high melting and boiling point brittle very strong
name some characteristics of graphite
each carbon atom has three bonds
they form a flat hexagonal structure
inbetween the layers there is a weak intermolecular force
the layers are able to slide over each other
useful in industry as solid lubricant
high melting and boiling point due to strong covalent bonds
name some characteristics of fullerene
balls of carbon due to shape they make a good lubricant (they roll) simple covalent molecules low melting point weak inter molecular force
name some properties of allotropes
giant covalent structures have high melting and boiling points (diamond and graphite)
simple covalent structures have a low melting and boiling point (fullerene)
Can giant covalent structures conduct electricity?
no - they do not have charged particles that can move.
BUT graphite can conduct electricity because it has delocalised electrons which can move between the sheets of carbon.
what are malleable metals?
Metals that can be hammered into shapes. They do this because the layers of metal ions are able to slide but are still held together by the sea of delocalised electrons
