Unit One, Chapter Five - Shapes Of Molecules And Polyatomic Ions

Question 1

How do we predict the shape of molecules and polyatomic ions?

Answer 1

By looking at the number of bonding electron pars and non-bonding electon pairs

Question 2

What is a dative covalent bond?

Answer 2

A bond in which one atom provides both electrons of the bonding pair

Question 3

Bond angle for the angular shape

Answer 3

120° with 1 lone pair, 104.5° with 2 lone pairs

Question 4

Bond angle of the pyramidal shape

Answer 4

107.5°

Question 5

Bond angle of the tetrahedral shape

Answer 5

109.5°

Question 6

List electron pair repulsions in decreasing strength order

Answer 6

Lone pair/lone pair → lone pair/bonding pair → bonding pair/bonding pair

Question 7

Electron pairs → arrangement (table)

Answer 7

2 → linear
3 → trigonal
4 → tetrahedral
5 → trigonal bipyrimidal
6 → octahedral

Question 8

Formula for number of electron pairs (in an ion)

Answer 8

((Electrons in central atom +/- x) + number of atoms attached) /2

Question 9

Formula for number of electron pairs (in a molecule)

Answer 9

(Electrons of central atom + number of atoms attached) /2