Bonding

Question 1

What is ionic bonding?

Answer 1

bonding that usually occurs between a metal and a non-metal. Electrons are transferred, forming ions. These oppositely charged ions have strong forces of electrostatic attraction between them, forming a giant ionic lattice

Question 2

What is covalent bonding?

Answer 2

. It involved pairs of electrons, that are shared between two atoms. These bonds form either simple molecular or giant covalent structures

Question 3

What is a dative covalent bond?

Answer 3

A covalent bond when both the shared electrons are supplied from the same atom (e.g NH4+)

Question 4

How do dative covalent bonds react?

Answer 4

exactly the same as covalent bonds

Question 5

What is metallic bonding?

Answer 5

bonding that occurs in metals. Positive metals ions in a sea of delocalised electrons. Strong electrostatic attraction between positively charged metal ions and delocalised electrons. Forms a giant metallic lattice

Question 6

How does the size of a metal ion impact the strength of the electrostatic forces present?

Answer 6

larger ions have weaker electrostatic forces of attraction, due to the increased distance between the positively charged nucleus and the delocalised electrons.

Question 7

What are the 4 types of crystal structures?

Answer 7

ionic, metallic, macromolecular/giant covalent and simple molecular

Question 8

Describe and explain the melting point of ionic structures

Answer 8

they have high melting and boiling points. This is due to strong electrostatic forces of attraction between oppositely charged ions.These require lots of energy to overcome.

Question 9

Describe and explain the conductivity of ionic structures

Answer 9

they cannot conduct when solid but can when molten. This is because, when molten, the ions are able to move and carry charge

Question 10

Why are ionic structures often brittle?

Answer 10

They are arranged in layers. If one layer moves, then it may cause like charges (on ions) to repel each other, and break apart the structure

Question 11

Describe and explain the conductivity of metallic structures

Answer 11

They are often good conductors. The sea of delocalised electrons can carry charge and move throughout the structure

Question 12

Why are metals often malleable?

Answer 12

as they are arranged in layers, which can slide over each other. There is no fragmentation as the delocalised electrons can move

Question 13

Describe and explain the melting point of metallic structures

Answer 13

high melting and boiling points, due to strong electrostatic forces of attraction between positive metal ions and delocalised electrons, these require lots of energy to overcome

Question 14

Describe and explain the melting point of simple molecular structures

Answer 14

low melting and boiling points, as the only inter-molecular forces present are weak Van Der Waals, these require little energy to overcome.

Question 15

Describe and explain the conductivity of simple molecular structures

Answer 15

Do not conduct, as there are no charged particles present

Question 16

Describe and explain the melting point of macro-molecular structures

Answer 16

very high boiling and melting points due to the giant lattice structure held together by very strong covalent bonds, that require lots of energy in order to overcome

Question 17

Why can graphite conduct electricity?

Answer 17

As it is arranged in layers which have delocalised electrons, that can carry charge throughout the structure

Question 18

What determines the shape of a molecule?

Answer 18

the electrons/bonding pairs that surround the central atom. they repel each other, causing the largest possible bond angle to occur

Question 19

How does repulsion from a lone pair compare to repulsion from a bonding pair?

Answer 19

lone pairs repel more (covalent bonds reduced by approx. 2.5 deg. for each lone pair present)

Question 20

What is the bond angle of a non-linear/bent molecule?

Answer 20

104.5 degrees

Question 21

What is the bond angle of a trigonal planar molecule?

Answer 21

120 degrees

Question 22

What is the bond angle of a triangular pyramid molecule?

Answer 22

107 degrees

Question 23

What is the bond angle of a tetrahedral molecule?

Answer 23

109.5 degrees

Question 24

What are the bond angles in a trigonal bi-pyramid molecule?

Answer 24

90 and 120 degrees

Question 25

What is the bond angle in a octahedral molecule?

Answer 25

90 degrees

Question 26

What is meant by the term ‘electronegativity’?

Answer 26

the tendency of an atom to attract the bonding pair of electrons in a covalent bond

Question 27

What is a permanent dipole?

Answer 27

an uneven distribution of charge caused by a large difference in electronegativity

Question 28

What is an induced dipole?

Answer 28

an uneven distribution of charge that occurs when the electrons are influenced by another charged particle

Question 29

Why do Van Der Waals increase in strength with straight-chain molecules?

Answer 29

they are able to pack more closely together , reducing the distance over which the force acts, causing stronger attraction

Question 30

What are hydrogen bonds?

Answer 30

bonds that form between either O, N or F and a Hydrogen molecule. They are the strongest intermolecular force

Question 31

Draw KrF2

Answer 31

2 x f atoms, 3 x lone pairs
based on trigonal bipyramidal

Question 32

Why is CBr4 not a polar molecule?

Answer 32

• it is tetrahedral/symmetrical
• so dipoles/charges cancel out

Question 33

Why has CBr4 got a higher bpt. than CHBr3?

Answer 33

• CBr4 has Van Der Waals
• CHBr3 has dipole-dipole interactions and VDWs
• CBr4 has stronger VDWs as it has more electrons