structure and bonding Flashcards
what is the structure of an ionic compound?
- Giant lattice structure
- Made of crystals
- Positive ions &
negative ions - Strong electrostatic
forces between
oppositely charged
ions
what are the physical properties of ionic compounds?
- giant ionic lattice
- strong forces of attraction between oppositely charges ions
- these require lots of energy to break
- Ions are free to move and carry an electrical charge when molten or dissolved in water.
- As a solid, the ions are held in fixed
positions.
ionic compounds are solid at room temperature, so have high melting points and boiling points. why?
- giant ionic lattice
- strong forces of attraction between oppositely charges ions
- these require lots of energy to break
ionic compounds conduct electricity when molten or
dissolved in water, but not as a solid. why?
- Ions are free to move and carry an electrical charge when molten or dissolved in water.
- As a solid, the ions are held in fixed
positions.
what is a covalent bond?
A covalent bond is the force of attraction between a shared pair of electrons and 2 nuclei.
What are the properties of simple molecular substances?
- Simple molecular substances have low melting and boiling points because the forces of attraction between molecules are weak, so small amounts of energy are needed to break them. The covalent bonds in the molecules are not broken.
-As the size of the molecule increases,
the strength of the intermolecular forces
increases. - Simple molecular substances do not have any free charged particles. This means they do not conduct electricity.
what is a giant covalent substance?
An allotrope of an element is the same element
but with its atoms bonded in a different way. Two allotropes of carbon are diamond and graphite.
Each allotrope contains many carbon atoms
bonded together by strong covalent bonds.
describe the properties of a giant covalent substance when it has a rigid/lattice structure.
- it has a high melting and boiling point because lots of strong lots of covalent bonds need to be broken.
- it’s very hard because the atoms are bonded together in a rigid network.
- doesn’t conduct electricity because it has no free charged particles.
describe the properties of a giant covalent substance when it has layers of atoms that can slide over each other.
- it has a high melting and boiling point because lots of strong lots of covalent bonds need to be broken.
its soft and slippery because layers of delocalised electrons slide over eachother. - conducts heat and electricity because the delocaslied electrons can move.
what is the structure of metals?
Metals exist as giant metallic lattices . To get a full
outer shell of electrons, each metal atom loses its outer
electrons to a ‘sea’ of delocalised electrons.
what are the properties of metals?
I. Metals have very high melting + boiling points because there are strong forces of attraction between the sea of
delocalised electrons and positive metal ions.
2. Metals are good conductors of heat and electricity because the delocalised electrons can move.
3. Metals are malleable (When a material can be easily beaten into shape) and ductile (When a material can be easily pulled into wires) because of the layers of ions can slide over each other.
what is the charge of metals in group 1,2 and 3?
the charge = the group number
eg. if group is 2 = charge is 2+
what is the charge of non metals in group 5,6 and 7?
the charge = group number = 8
eg. if group is 5 = charge is 3-
name the formula for the following silver copper iron (2) iron (3) lead zinc
Ag+ Cu2+ Fe2+ Fe3+ Pb2+ Zn2+
namer the formula for the following hydrogen hydroxide ammonium carbonate nitrate sulfate
H+ OH- NH4+ CO3^2- NO3- SO4^2-
