Bonding and structure - 2

Question 1

What are the 3 types of chemical bonds

Answer 1

Ionic
Covalent
Metallic

Question 2

Define ionic bonding

Answer 2

The electrostatic attraction between positive and negative ions

Question 3

Define covalent bonding

Answer 3

Electrostatic attraction between a shared pair of electrons and the nuclei

Question 4

Define metallic bonding

Answer 4

Electrostatic attraction between the positive metal ions and the delocalised electrons

Question 5

Why does giant ionic latices conduct when liquid but no when solid

Answer 5

Solid state the ions are in fixed positions and cannot move
When in liquid the ions are free to move and can carry charge freely

Question 6

Why do giant ionic structures have a high boiling/melting point

Answer 6

A large amount of energy is required to overcome the electrostatic bonds

Question 7

What types of solvents dissolve ionic lattices

Answer 7

Polar solvents

Question 8

Why are ionic compounds soluble in water

Answer 8

Water has polar bonds
Hydrogen atoms have a + charge and oxygen has a - charge
These can attract charged ions

Question 9

what is a lone pair

Answer 9

Electrons in the outer shell that are not involved in bonding

Question 10

What is average bond enthalpy

Answer 10

Measure of average energy needed to break the bond

Question 11

What is a dative covalent bond

Answer 11

A bond where both of the shared electrons are supplied by one atom

Question 12

What are the types of covalent structures

Answer 12

Simple molecular
Giant covalent

Question 13

Describe the bonding in simple molecular structures

Answer 13

Atoms are held by strong covalent bonds and different molecules are held by weak intermolecular forces

Question 14

Why do simple molecular have low melting/boiling points

Answer 14

Small amounts of energy needed to overcome the intermolecular forces

Question 15

Why do simple molecular structures not conduct electicity

Answer 15

They have no free charged particles to move

Question 16

What solvents dissolve simple molecular substances

Answer 16

Non polar solvents

Question 17

List 3 properties of giant covalent

Answer 17

High melting/boiling points

Non conductors

Insoluble in polar and non-polar

Question 18

How doe graphite conduct electricity

Answer 18

Delocalised electrons present between the layers are able to move freely carrying the charge

Question 19

Why do giant covalent structures have high melting/boiling points

Answer 19

Strong covalent bonds within the molecules need to be broken which requires a lot of energy

Question 20

What does the shape of the molecule depend on

Answer 20

Number of electron pair in the outer shell

Number of these electrons

Question 21

What is the shape and bond angle in a shape with 2 bonded pairs and 0 lone pairs

Answer 21

Linear
180

Question 22

What is the shape and bond angle in a shape with 3 bonding pairs and 0 lone pairs

Answer 22

Trigonal planar
120

Question 23

What is the shape and bond angle in a shape with 4 bonded pairs and 0 lone pairs

Answer 23

Tetrahedral
109.5

Question 24

What is the shape and bond angle in a shape with with 5 bonded pairs and 0 lone pairs

Answer 24

Trigonal Bipyramid
90 and 120

Question 25

What is the shape and bond angle in a shape with 6 bonded pairs and 0 lone pairs

Answer 25

Octahedral 90

Question 26

What is the shape and bond angle of a shape with 3 bonding pairs and 1 lone pair

Answer 26

Pyramidal 107

Question 27

What is the shape and bond angle in a shape with 2 bonded pairs and 2 lone pairs

Answer 27

Non Linear 104.5

Question 28

By how many degrees does each lone pair reduce the bond angle

Answer 28

2.5

Question 29

Define electronegativity

Answer 29

The ability of an atom to attract the pair of electrons in a covalent bond

Question 30

Which direction of the periodic table does electronegativity increase

Answer 30

Top right, towards fluorine

Question 31

What does non-polar in a bond mean

Answer 31

The electrons in the bond are evenly distributed

Question 32

what is the most electronegative element

Answer 32

Fluorine

Question 33

How is a polar bond formed

Answer 33

Bonding atoms have different electronegativities

Question 34

What are the types of intermolecular forces

Answer 34

Hydrogen bonding Permanent dipole-dipole interactions London dispersion forces

Question 35

What is the strongest type of intermolecular forces

Answer 35

Hydrogen bonding

Question 36

Describe permanent dipole dipole interactions

Answer 36

When molecules with a permanent dipole is close to other non polar molecules It causes the non polar

Question 37

Describe London dispersion forces

Answer 37

Caused by random movements of electrons This leads to instaneous dipoles Instantaneous dipole induces a dipole in nearby molecules Induced dipoles attract one another

Question 38

Are London forces greater in smaller or larger molecules

Answer 38

Larger due to more electrons

Question 39

Does boiling point increase or decrease down the noble gas group

Answer 39

Boiling point increases because the number of electrons increase, so there are stronger london dispersion forces

Question 40

Why is ice less dense than water

Answer 40

In ice water molecules are arranged in a orderly pattern. It has a open lattice with hydrogen bonds In water the lattice is collapsed and the molecules are closer together

Question 41

Why does water have a higher boiling point than expected

Answer 41

Hydrogen bonds are stronger than other intermolecular forces, so extra strength is required to overcome the forces