3.1.3 bonding

Question 1

define ionic bonding

Answer 1

electrostatic attraction between oppositely charged ions in a lattice

Question 2

define covalent bonding

Answer 2

a single covalent bond contains a shared pair of electrons

Question 3

what is a dative bond?

Answer 3

a covalent bond that contains a shared pair of electrons with both electrons supplied by one atom

Question 4

define metallic bonding

Answer 4

attraction between delocalised electrons and positive ions arranged in a lattice

Question 5

what are the four crystal structures?

Answer 5

ionic
metallic
macromolecular
molecular

Question 6

can metallic substances conduct electricity and why?

Answer 6

yes they can conduct electricity.
there are delocalised electrons that are free to move

Question 7

define molecular

Answer 7

isolated molecules containing covalent bonds

Question 8

in terms of lone pairs and bonding pairs what is the strength of repulsion?

Answer 8

repel the least : bonding pair - bonding pair
repel the most : lone pair - lone pair

Question 9

how do you work out the shape of a molecule?

Answer 9

• find the group number of the central atom
• count how many electrons are involved in bonding
• count how many electrons are left over

Question 10

what is the name of the shape with 2 bonding pairs and 0 lone pairs?

Answer 10

linear 180°

Question 11

what is the name of the shape with 3 bonding pairs and 0 lone pairs?

Answer 11

trigonal planar 120°

Question 12

what is the name of the shape with 3 bonding pairs and 0 lone pairs?

Answer 12

trigonal planar 120°

Question 13

what is the name of the shape with 2 bonding pairs and 1 lone pair?

Answer 13

bent ( v shape ) angle less than 120°

Question 14

what is the name of the shape with 4 bonding pairs and 0 lone pairs?

Answer 14

tetrahedral 109.5°

Question 15

what is the name of the shape with 3 bonding pairs and 1 lone pair?

Answer 15

trigonal pyramidal 107°

Question 16

what is the name of the shape with 2 bonding pairs and 2 lone pairs?

Answer 16

bent ( v shape ) 104.5°

Question 17

what is the name of the shape with 5 bonding pairs and 0 lone pairs?

Answer 17

trigonal bipyramidal 90° and 120°

Question 18

what is the name of the shape with 4 bonding pairs and 1 lone pairs?

Answer 18

see saw less than 120° less than 90°

Question 19

what is the name of the shape with 3 bonding pairs and. 2 lone pairs?

Answer 19

T- Shape
less than 120°

Question 20

what is the name of the shape with 6 bonding pairs and 0 lone pairs?

Answer 20

octahedral 90°

Question 21

what is the name of the shape with 5 bonding pairs and 1 lone pair?

Answer 21

square pyramid less than 90°

Question 22

what is the name of the shape with 4 bonding pairs and 2 lone pairs?

Answer 22

square planar 90°

Question 23

define electronegativity

Answer 23

the power of an atom to attract a shared pair of electrons in a covalent bond

Question 24

what are the trends in electronegativity?

Answer 24

increases across a period
decreases down a group

Question 25

explain how electronegativity increases across a period

Answer 25

- shielding effect is constant - nuclear charge increases - atomic radius decreases - attraction between nucleus and shared pair of electrons increases

Question 26

what makes a bond polar?

Answer 26

when 2 atoms with different electronegativities covalently bond, one atom will attract the shared pair more strongly leading to unequal distribution of the shared pair

Question 27

what are the 3 types of intermolecular forces?

Answer 27

van der waals permanent dipole dipole hydrogen

Question 28

what are the factors that affect strength of van der waals?

Answer 28

- size of molecule - points of contact between molecules

Question 29

how does the size of the molecule affect strength of van der waals?

Answer 29

the bigger the molecule the more electrons it contains and the greater the charge of the imbalance of the temporary dipole. This causes stronger van der waals between forces

Question 30

how do points of contact affect the strength of van der waals?

Answer 30

straight chained organic molecules can pack closer together than branched molecules leading to more points of contact and stronger van der waals forces

Question 31

what elements exhibit hydrogen bonding?

Answer 31

oxygen nitrogen fluorine

Question 32

what are properties that arise due to hydrogen bonding?

Answer 32

ice has a lower density than water