3C.2 Shapes of molecules and ions

Question 1

what does the electron pair repulsion theory state (VSEPR)

Answer 1

A molecule or an ion’s shape is caused by the repulsion of the electron(bond pairs and lone pairs) in the central shell. the electron pairs arrange themselves around the central atom to keep the repulsion between them at a minimum. lone pair-lone pair repulsion> lone pair-bonded pair repulsion> bond pair-bond pair repulsion (this determines the bond angles

Question 2

how do you find the shape of molecules and ions

Answer 2

you do that by finding the number of bond pairs and lone pairs of electrons around the central atom (dot cross diagram)

Question 3

molecules with multiple bonds

Answer 3

the best way to deal with it is to treat each multiple bonded as it only contains one election

Question 4

what are the types of shapes molecule and form

Answer 4

1. linear (2 bonds)
2. trigonal planar (3 bonds)
3. tetrahedral (4 bonds)
4. trigonal bipyramidal (5 bonds)
5. octahedral (6 bonds)
6. trigonal pyramidal (3 bonds)
7. v-shaped (2 bonds0

Question 5

what angle do the linear form and an example

Answer 5

180 BeCl2

Question 6

what angle do the trigonal planar form and an example

Answer 6

120 BCl3

Question 7

what angle do the tetrahedral form and an example

Answer 7

109.5 CH4 or NH4

Question 8

what angle do the trigonal bipyramidal form and an example

Answer 8

120 between and 90 PCl3

Question 9

what angle do the octahedral form and an example

Answer 9

90 SF6 because the f are opposite one another

Question 10

what angle do the trigonal pyramidal form and an example and why

Answer 10

107 NH3 because the lone pair-bond pair repulsion is stronger than the bond pair-bond pair repulsion

Question 11

what angle do the V-shaped form and an example and why

Answer 11

104.5 H2O since the lone pair-lone pair repulsion is stronger than lone pair-bond pair repulsion it would be less than 109