Shapes Of Molecules and Intermolecular Forces

Question 1

What does the arrangement of electron pairs do?

Answer 1

Minimises repulsion and holds the bonded atoms in a definitive shape

Question 2

What causes different shapes?

Answer 2

Different numbers of electron pairs

Question 3

What shape is it if there are four electron powers?

Answer 3

Tetrahedral

Question 4

What is the bond angle in a tetrahedral shape?

Answer 4

109.5degress

Question 5

Why is a lone pair more stronger repelling than a bonded pair of electrons?

Answer 5

A lone pair of electrons is slightly closer to the central atom and occupies more space

Question 6

What shape is the molecule if there are 3 bonded pairs and one lone pair?

Answer 6

Pyramidal

Question 7

What is the bond angle of a pyramidal molecule?

Answer 7

107degress

Question 8

What is the shape of a water molecule?

Answer 8

Bent linear

Question 9

What is the bond angle in a non linear shape? (Bent linear)

Answer 9

104.5degrees

Question 10

What makes the bond angle smaller?

Answer 10

More electron pairs

Question 11

What angle does a trigonal planar molecule have?

Answer 11

120 degrees

Question 12

What bond angle does an octahedral molecule have?

Answer 12

90 degrees

Question 13

What is electronegativity?

Answer 13

The attraction of a bonded atom for the pair of electrons in a covalent bond

Question 14

What scale measures electronegativity?

Answer 14

The Pauling scale

Question 15

What happens as you go right across the periodic table?

Answer 15

The electronegativity increases

Question 16

What happens as you travel up the periodic table

Answer 16

The electronegativity increase

Question 17

What happens in a covalent molecule if there is a difference in electronegativity?

Answer 17

The covalent bond is pulled closer to the atom with more electronegativity

Question 18

Describe an ionic bond in terms of electronegativity

Answer 18

Large electronegativity difference
One atom has more of an attraction to the shared pair
More electronegative atom gained control of electrons

Question 19

What determine the shape of the molecule?

Answer 19

The electron pairs surrounding a central atom

Question 20

What is a non polar bond?

Answer 20

Where the bonded electron pair is shared equally between the bonded atoms

Question 21

When will there be a non polar bond?

Answer 21

When the bonded atoms are the same

The bonded atoms have the same or similar electronegativity

Question 22

What is a polar bond?

Answer 22

Where the bonded electron pair is shared unequally between the atoms

Question 23

What is a non polar bond also called?

Answer 23

A pure covalent bond

Question 24

Give an example of a polar molecule

Answer 24

Water

Question 25

What are intermolecular forces?

Answer 25

Weak interactions between dipoles of different molecules

Question 26

What are the three types of intermolecular forces?

Answer 26

Induced dipole to dipole (ldf) Permanent dipole to dipole Hydrogen bonding

Question 27

What are intermolecular forces responsible for?

Answer 27

Physical properties eg melting and boiling points

Question 28

How is an induced dipole created?

Answer 28

The movement of electrons creates a changing dipole in a molecule Creating constantly shifting instantaneous dipole Which induces a dipole on its neighbour And so on

Question 29

What happens to the ldf the more electrons are in a molecule?

Answer 29

Larger the instantaneous and induced dipole Greater induced dipole to dipole interactions Stronger attractive forces between molecules

Question 30

Where do permanent dipoles happen?

Answer 30

Between the dipoles in polar molecules

Question 31

Are simple molecular forces soluble in polar solvents?

Answer 31

No

Question 32

Where is a hydrogen found between?

Answer 32

Molecules containing: An electronegative atom with a lone pair of electrons A hydrogen atom attached to an electronegative atom

Question 33

What does the hydrogen bond act between?

Answer 33

The lone pair of electrons on me molecule and the hydrogen atom on the other molecule

Question 34

What gives water it's weird properties?

Answer 34

The hydrogen bonding

Question 35

Why is ice less dense than water?

Answer 35

Hydrogen bond holds water further apart in an open lattice structure with holes in it decreasing its density