C2 Bonding, Structures and Properties Flashcards
what does ionic bonding occur with?
metals + non-metals
what will the electrons go from in ionic bonding?
metal to non-metals
how does an ionic bond from between sodium and chlorine?
The sodium atom (transfers) loses one electron to the chlorine atom to form a sodium ion.
The chlorine atom gains one electron from the sodium atom to form a chlorine ion.
The electrostatic force of attraction between the atoms are reasonably stronger which forms an ionic bond
what are the 3 properties of ionic substances?
- high melting and boiling points
- conducts electricity when molten and dissolved
- usually soluble in water (inorganic solvent)
why do ionic substances have high melting and boiling points?
they have strong forces of attraction between oppositely charged ions, these require a lot of energy to break
why do ionic substances conduct electricity?
charged ions are free to move and carry electrical charge
why are ionic substances usually soluble in water?
water has a positive and negative end so ionic ions attract and dissolve
what can the formula of ionic substances tell us?
the ratio of __ ions to __ ions
what does the formula Al2O3 tell us?
the ratio of Al3+ ions to O2+ ions in aluminium oxide is 2:3
what does covalent bonding happen between?
non-metal + non-metals
what does covalent bonding happen between?
non-metal + non-metals
what does covalent bonding involve?
the sharing of electrons
what does covalent bonding involve?
the sharing of electrons
why does covalent bonding happen?
to become stable / have a full outer shell
what are the 3 properties of covalent substances?
- low melting and boiling points
- cannot conduct electricity
- not soluble
why do covalent substances have low melting / boiling points?
have weak intermolecular forces that hold molecules together, when the substance boils these forces are overcome which don’t require much energy (not the strong covalent bonds)
why can’t covalent substances conduct electricity?
they don’t have free moving electrons or ions, molecules are neutral
why are covalent substances not soluble?
they are not charged
define allotrope
different structure of the same element under the same conditions
describe the structure of graphite
Hexagonal layered structure
Carbon atoms covalently bonded to 3 others
1 electron per carbon atom delocalised and free to move through the structure (conducts electricity)
There are weak intermolecular forces of attraction between the layers (brittle + why there are used in pencils)
what are the 2 properties of graphite?
- soft layers that can slide
- conducts electricity
why does graphite have soft layers that can slide?
weak intermolecular forces between layers
why does graphite conduct electricity?
the delocalised electron is free to move through the structure
describe the diamond structure
- tetrahedral structure, each carbon atom is bonded to 4 others
- no free electrons
- very hard
what are the properties of diamond?
- high melting points
- poor conductivity (insulator)
what are the properties of diamond?
- high melting points
- poor conductivity (insulator)