Bonding

Question 1

which substance uses metallic bonding?

Answer 1

the atoms in a metal are held together by metallic bonding. each metal atom is ionised and occupies fixed positions in the lattice.

Question 2

what is metallic bonding?

Answer 2

a strong attraction between the positive ions and negative delocalised electrons

Question 3

When comparing melting points of elements, what do you have to consider?

Answer 3

the charge
the charge density
the metallic bonding

Question 4

Between lithium and sodium, which has the higher melting point and why?

Answer 4

They are both in the same group,so have the same charge. However, lithium has a higher charge density so it has stronger metallic bonding and has a higher melting point.

Question 5

Between sodium and magnesium, which has the higher melting point and why?

Answer 5

They are both in the same period. However, the size of the atoms get smaller as you go across the period, so you get a higher charge density. Magnesium has a higher charge density so it has stronger metallic bonding and has a higher melting point.

Question 6

What is a disadvantage of this model?

Answer 6

the ions are too far apart

Question 7

what are the properties of metals?

Answer 7

they are good conductors of heat and electricity
they are strong
they are malleable and ductile
they are high melting point substances

Question 8

why are metals good conductors of heat and electricity?

Answer 8

they have delocalised electrons

Question 9

why are metals strong?

Answer 9

there is a high force of attraction between the positive atoms and the negative delocalised electrons

Question 10

why are metals strong?

Answer 10

there is a high force of attraction between the positive ions and the negative delocalised electrons

Question 11

why are metals malleable and ductile?

Answer 11

the atoms are in layers

Question 12

why are metals high melting point substances?

Answer 12

there is a high force of attraction between the positive atoms and the negative delocalised electrons

Question 13

When comparing the strength of atoms , what do you need to consider?

Answer 13

the charge of the ion
the size of the ion

Question 14

going down group 1, what happens to the strength of the atoms?

Answer 14

charge stays the same
size of ion increases
charge density decreases
weaker metallic bonding/ stronger FoA
lower melting point

Question 15

going across a period, what happens to the strength of the atoms?

Answer 15

charge increases
size of ion decreases
charge density increases
stronger metallic bonding/ stronger FoA
higher melting points

Question 16

Why might aluminium(660•C) have a higher boiling point than sodium(97•C)?

Answer 16

higher charge
smaller ion
higher charge density
stronger force of attraction

Question 17

what are the charges of these ions?:

sulfate, hydroxide, nitrate, carbonate, ammonium

Answer 17

sulfate SO42- hydroxide OH- nitrate NO3- carbonate CO32- ammonium NH4+

Question 18

what is ionic bonding?

Answer 18

occurs when two or more ions combine to form an electrically neutral compound

Question 19

what happens during ionic bonding?

Answer 19

the positive cation “loses” an electron and the negative anion “gains” the electron. the electrons are not shared between the two atoms, as the anion steals the electrons from the cation

Question 20

what does GIL stand for?

Answer 20

giant ionic lattice

Question 21

Can ionic compounds conduct electricity? why or why not?

Answer 21

no
they have a high melting point- there are many strong FoA between the positive ions and the negative ions, making it hard to break apart ionic compounds
conductivity- when dissolved in water or molten, ionic compounds conduct electricity. in water, the bonds dissociate(fall apart), leaving lots of ions to carry charge

Question 22

Between NaF and NaCl which had the higher melting point?

Answer 22

NaF because it is a smaller atom, has a higher charge density and strong FoA

Question 23

Between NaF and LiF, which has the higher melting point?

Answer 23

LiF because it is a smaller atom, has a higher charge density and strong FoA

Question 24

Between NaF and Na2O, which has the higher melting point?

Answer 24

Na2O. The O has a -2, and F has a -1 so Na2O has a higher charge and higher density and a stronger FoA.

Question 25

What is a covalent bond?

Answer 25

covalent bonds can be formed when a non metal reacts with a non metal atoms share electrons to attain a full outer shell the nuclei of each atom is attracted to the shared pairs of electrons

Question 26

how many bonds do 2 shared electrons make?

Answer 26

1

Question 27

how many bonds do 4 shared electrons make?

Answer 27

2

Question 28

how many bonds do 6 shared electrons make?

Answer 28

3

Question 29

How are alevel dot and cross diagrams drawn?

Answer 29

with lines

Question 30

draw an a level dot and cross diagram of sulfuric acid

Answer 30

Question 31

how is sulfuric acid an exception to the electron rule?

Answer 31

in the dot and cross diagram sulfur has 12 electrons. this shows that atoms don’t always have 8 electrons on their outer shell to be stable.

Question 32

draw the covalent bond of carbon dioxide

Answer 32

Question 33

draw the covalent bond of nitrogen

Answer 33

Question 34

draw the covalent bond of nitrogen

Answer 34

Question 35

what is the correlation between the number of bonds and the length of bonds ?

Answer 35

the more the bonds, the longer the bonds

Question 36

what is the correlation between the number of bonds and the strength of the bonds?

Answer 36

the more the bonds, the stronger the bonds

Question 37

In a covalent bond of bromine with fluorine, bromine only shares 6 electrons with flourine rather than 8(which is what is needed to get an outer shell). is this a problem?why/not?

Answer 37

no it’s not. boron has formed the maximum number of bonds that it can in the circumstances, and this is a perfectly valid structure.

Question 38

why doesn’t boron form ionic bonds with flourine instead?

Answer 38

the total energy needed to remove 3 electrons and form a 3+ ion is too great.

Question 39

electrons that are paired in a covalent bond are called?…

Answer 39

bonding pairs

Question 40

electrons that are not used in bonding do what?…

Answer 40

they pair and form lone pairs

Question 41

draw the Lewis structure for ammonia and show the lone pairs

Answer 41

Question 42

draw the Lewis structure for ammonia and show the lone pairs

Answer 42

Question 43

what is co-ordinate/dative covalent bonding?

Answer 43

A covalent bond in which both electrons come from the same atom. Lone pairs can be donated to the other atom It is sometimes drawn with an arrow rather than a dash

Question 44

Draw a dative covalent bond with water

Answer 44

Question 45

In a reaction between ammonia and hydrogen chloride, how are ammonium ions formed?

Answer 45

they are formed by the transfer of a hydrogen ion from the hydrogen chloride to the lone pair of electrons on the ammonia molecule.

Question 46

when hydrogen chloride dissolved in water to make hydrochloric acid, what happens?

Answer 46

A hydrogen ion is transferred from the chlorine to one of the lone pairs on the oxygen atom.

Question 47

what happens in the reaction between boron trifluoride and ammonia?

Answer 47

boron trifluoride as a compound doesn't have a noble gas structure around the boron atom. The boron only has 3 pairs of electrons in its bonding level, whereas there would be room for 4 pairs. boron flouride is described as being electron deficient. The lone pair on the nitrogen of an ammonia molecule can be used to overcome that deficiency, and a compound is formed involving a co-ordinate bond.

Question 48

To determine the shape of a compound, what pieces of information do we need to know?

Answer 48

Central atom Group - this tells you the outer e Charge - remember + means lose an e Bonds - number of bonds Total - add up 2+3+4 Divide by two = number of pairs ofe Structure (not shape) Look at 6 and 4 to work out if any lone pairs Shape Bond angle(s)

Question 49

When drawing a shape, what do you need to remember?

Answer 49

all pairs of electrons are trying to repel each other as far apart as possible

Question 50

what is the shape and angle of a structure with 2 bond pairs?

Answer 50

linear 180degrees

Question 51

what is the shape and angle of a structure with 3 bond pairs?

Answer 51

trigonal planar 120 degrees

Question 52

what is the shape and angle of a structure with 4 bond pairs?

Answer 52

tetrahedral 109.5degrees

Question 53

what is the shape and angle of a structure with 5 bond pairs?

Answer 53

trigonal biprymidal 120/90 degrees

Question 54

what is the shape and angle of a structure with 6 bond pairs?

Answer 54

octahedral 90 degrees

Question 55

what is the name of the shape of methane (CH4)?

Answer 55

tetrahedral

Question 56

what do the different bond styles tell you?

Answer 56

straight line=bond in the plane of the paper triangle shape line=bond coming out of the paper dashed line=bond going into the paper

Question 57

Draw the shape of methane and explain the bonds

Answer 57

A diagram of a methane molecule. Two bonds are in the plane of the paper, the middle one comes out towards you and the left hand bond goes away from you.

Question 58

Draw the shape of sulfur hexafluoride

Answer 58

Question 59

Draw the shape of sulfur hexafluoride

Answer 59

Question 60

Draw the shape of sulfur hexafluoride

Answer 60

Question 61

What are the bond angles in sulfur trioxide molecule?

Answer 61

always 120 degrees

Question 62

What is the electron pair repulsion theory?

Answer 62

Predicts the shapes of simple molecules. Considers the repulsions between pairs of electrons (lone pair and bonding pair) within the molecule. All electrons in bonds are trying to repel each other as far apart as possible Lone pairs have a greater repulsive force

Question 63

What is the impact of a lone pair on the bond angles?

Answer 63

Lone pairs will affect the angles of bonds as they push the bonding pairs away. -2.5 degrees

Question 64

Ammonia has a lone pair. What is its new bond angle and shape?

Answer 64

107degrees angular

Question 65

Ammonia has a lone pair. What is its new bond angle and shape?

Answer 65

107degrees angular

Question 66

Water has two lone pairs . What is its new bond angle and shape?

Answer 66

104.5degrees angular

Question 67

what are the common shapes?

Answer 67

4 bonding pairs-tetrahedron 3bp and 1lp-trifocals pyramid 2bp 2lp-angular

Question 68

what is an uncommon shape?

Answer 68

1bp 3lp

Question 69

what name does trigonal planar change to if it has 1lp

Answer 69

angular

Question 70

what name does tetrahedral change to if it has 1lp

Answer 70

trigonal pyramid

Question 71

what name does tetrahedral change to if it has 2lp

Answer 71

angular

Question 72

what name does trigonal bipyramidal change to if it has 1lp

Answer 72

“see-saw”

Question 73

what name does trigonal bipyramidal change to if it has 2lp

Answer 73

t-shaped

Question 74

what name does trigonal bipyramidal change to if it has 3lp

Answer 74

linear

Question 75

what name does octahedral change to if it has 1lp

Answer 75

square pyramidal

Question 76

what name does octahedral change to if it has 2lp

Answer 76

square planar

Question 77

Predict the shape of PCl4+

Answer 77

tetrahedral

Question 78

Predict the shape of CH3+

Answer 78

trigonal planar

Question 79

Predict the shape of IF4-

Answer 79

square planar

Question 80

Presdict the shape of IF4-

Answer 80

square planar

Question 81

What is a polar bond

Answer 81

a bond that had a delta positive and delta negative region

Question 82

what is electronegativity

Answer 82

the ability to attract bonding electrons in a covalent bond

Question 83

Explain bond polarity

Answer 83

In a covalent bond between two atoms of different electronegativities, the bonding electrons are pulled towards the more electronegative atoms. This makes the bond polar. The greater the difference in electronegativity, the more polar the bond

Question 84

What are the factors that affect electronegativity?

Answer 84

nuclear charge distance between nucleus and shared pair of electrons

Question 85

What does the difference in electronegativity cause?…

Answer 85

a permanent dipole

Question 86

What causes a permanent dipole?

Answer 86

if a charge is distributed unevenly over a whole molecule, then the molecule will have a permanent dipole

Question 87

does carbon dioxide have a permanent dipole

Answer 87

no

Question 88

does hydrochloric acid have a permanent dipole

Answer 88

yes

Question 89

does hydrochloric acid have a permanent dipole

Answer 89

yes

Question 90

What do Van der Waals forces do?

Answer 90

they cause all atoms and molecules to be attracted to each other

Question 91

How do VDW forces work ?

Question 92

As the VDW forces increase, what happens to the boiling point?(noble gases)

Answer 92

increases

Question 93

how are the number of electrons and size of VDW forces linked?

Answer 93

the more electrons, the stronger the VDW forces

Question 94

How is a hydrogen bond formed?

Answer 94

when a lone pair of electrons from one molecule interacts with a hydrogen on another molecule

Question 95

What is a hydrogen bond?

Answer 95

A very strong intermolecular attraction ( an only happen between hydrogen and N,O or F)

Question 96

Draw the hydrogen bonding structure of water

Answer 96

Question 97

Draw the hydrogen bonding structure of ammonia

Answer 97

Question 98

What is the importance of hydrogen bonding

Answer 98

-ice is less dense than water -water had a much higher melting and boiling point than would be expected expected -protein folding -DMA base pairing -enzyme reactions