Week Five

Question 1

How electrons arrange

Answer 1

arrange themselves as far away as possible

Question 2

Lewis model - deficiencies

Answer 2

H2 and F2 are treated equivalently by lewis dot model

Question 3

Valence bond theory

Answer 3

assumes electrons in a molecule occupy atomic orbitals

presumes electron density is equally shared

Question 4

sigma bond

Answer 4

a single bond that is formed by the overlap of the 2 1s shells

Question 5

overlap of a s and p orbital

Answer 5

sigma bond

Question 6

every first bond

Answer 6

sigma bond

Question 7

Hybridisation

Answer 7

when covalent bonds are formed atomic orbitals mix or hybridise to form new sets of orbitals

Question 8

how many orbitals in hybridisation

Answer 8

must have the same amount as started with

Question 9

pi bonds

Answer 9

formed by the sideways overlap of 2p orbitals

Question 10

electron density - pi bonds

Answer 10

above and below the axis joining the two atoms

Question 11

sigma bond strength

Answer 11

stronger than pi bonds because sideways overlap is not as effective as the end on bond

Question 12

single bond

Answer 12

sigma

Question 13

double bond

Answer 13

one sigma one pi

Question 14

triple bond

Answer 14

one sigma and 2 pi

Question 15

sp

Answer 15

linear

Question 16

sp2

Answer 16

trigonal

Question 17

sp3

Answer 17

tetrahedral

Question 18

sp3d

Answer 18

trigonal byprimidal

Question 19

sp3d2

Answer 19

octahedral

Question 20

Molecular orbital theory - predictions

Answer 20

accurate structures
dissociation energies
line positions
paramagnetism and diamagnetism

Question 21

molecular orbital theory - molecular bonds

Answer 21

treat them as a sharing of electrons between 2 nuclei

treats as delocalised, spread out

Question 22

bonding orbital

Answer 22

has lower energy so more stable

fills first

Question 23

anti bonding orbital

Answer 23

has higher energy less stable

will fill last

Question 24

sigma orbital

Answer 24

bonding molecular orbital with cylindral symmetry about an inter nuclear axis

Question 25

bond order

Answer 25

stability of molecule | 1/2 ( electrons in bonding orbital - number in anti bonding orbitals)

Question 26

net bond order of 0

Answer 26

wont form bond

Question 27

diamagnetic

Answer 27

no unpaired spins, cant interact in a magnetic field

Question 28

paramagnetic

Answer 28

has unpaired spins

Question 29

Heteronuclear diatomics

Answer 29

if they have same electronegativity they have similar diagram to homonuclear

Question 30

Acids

Answer 30

sour taste corrosive conduct electricity

Question 31

bases

Answer 31

bitter soapy corrosive conduct electricity

Question 32

strong

Answer 32

dissociates fully in water

Question 33

weak

Answer 33

partially dissociates

Question 34

Arrenhius acids and bases

Answer 34

form solvated hydrogen cations written as H+ or H3O+ | Arrenhius bases form hydroxide OH-

Question 35

Bronsted Lowry acids bases

Answer 35

acids are protons donors | bases proton acceptors

Question 36

Lewis acid and bases

Answer 36

acids act as electron pair acceptors | bases act as electron pair donors

Question 37

Monoprotic acids

Answer 37

acids ionise to form one H+ ion for every acid molecule

Question 38

Diprotic acids

Answer 38

produces 2H+ ions for every acid molecule

Question 39

Kw

Answer 39

equilibrium constant | [H3O+][OH-]

Question 40

ph

Answer 40

-log[substance]

Question 41

strong bases

Answer 41

fully dissociate in water to give metal cation and hydroxide ions `

Question 42

neutralisation reactions

Answer 42

when acids and bases are mixed

Question 43

pOH

Answer 43

-log[OH-]

Question 44

pH + pOH

Answer 44

14.00 at 25 degrees

Question 45

acidity constant

Answer 45

ka = [H3O+][A] -------------------------- [HA]

Question 46

Acid constant equation

Answer 46

HA +H2O => H3O+ + A-

Question 47

Basicity constant

Answer 47

Kb = [BH+] [OH-] ------------------------- [B]

Question 48

Basicity constant equation

Answer 48

B + H2O => BH+ + OH-

Question 49

Ka + Kb

Answer 49

Kw

Question 50

tha larger the Ka value

Answer 50

stronger the acid

Question 51

the smaller the pKa value

Answer 51

stronger the acid