Structure Flashcards
Name compounds, elements or ions which are tetrahedral.
Methane 109.5
Ammonium ion 109.5
Sulfate ion 109.5
Name compounds, elements or ions which are trigonal planar
Boron trichloride 120
Carbonate ion 120
Nitrate ion 120
Name compounds, elements or ions which are bent
Water 104.5
Sulfur dioxide 120
Name compounds, elements or ions which are trigonal bypyrimidal
Phosphorus pentachloride (in gas phase) 90 & 120
Name compounds, elements or ions which are pyramidal
Ammonia 107
Name compounds, elements or ions which are octahedral
Sulfur hexafluoride 90
Name compounds, elements or ions which are linear + state their bond angle
Carbon dioxide 180
Beryllium chloride 180
Hydrogen Chloride 180
Why is sulfur dioxide bent?
The lone pair and a bonding pair repel more than a bonding pair and a bonding pair
Why is ammonia pyramidal?
There are 3 bonded pairs and one lone pair of electrons. The bonded pairs repel less with each other than the lone pair and the bonded pair which results in a pyramidal shape.
Marking points for why one angle MAY be smaller than the other?
Extra lone pair
Lone pairs repel more
Bonding pairs are pushed closer together
Why are bond angles the angle they are?
to minimise repulsion of electron pairs
equation for working out the number of lone pairs
1/2 x [group number of the element - number of covalent bonds (not including covalently bonded lone pairs bc don’t know what they are!]
go to phrase about repulsions
lone pair-lone pair repulsions are greater than lone pair-bonding pair repulsions which are greater than bonding-bonding pair repulsions
analogous molecules to:
1) CH4
2) NH3
3) H2O
1) CH4 —> SiH4
2) NH3 —> PH3
3) H2O —-> H2S
How many lone pairs does ammonia (NH3) have?
1
How many lone pairs does wat have?
2
How many lone pairs does sulphur dioxide (SO2) have?
1
carbonate and nitrate ions both have…
two single bonds, one double (two snakes, one den)