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inorganic sem1 > john 2 > Flashcards

john 2 Flashcards

1
Q

across period 2 Li Be etc, what is bond strength determined by

A

the bond order of each one determined by MO theory.

0 bo = weakest bond, bond doesn’t exist between the 2

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2
Q

highest and lowest bond strength for period 2 elements

A

highest bond strength = N2 (3)
lowest bond strength = Be2 (0)

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3
Q

what causes the zig zag like bond strength tree in period 2

A

first: bonding orbitals are not filled so low strength

2nd: antibonding orbitals are being filled so lower strength

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4
Q

what state are N O and F at room temp

A

diatomic gases

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5
Q

what are Li Be B and C in room temp

A

solids

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6
Q

diatomic period 2 strongest bond

A

N2
bond order of 3
(use mo diagram)

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7
Q

single molecular period 2 strongest bonding

A

C
(graphite and diamond)
based on enthalpy of atomisation ( s-> g)

period 3 follows the same trend with group 14, Si on top

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8
Q

what period have the greatest enthalpy of atomisation

A

2
3 is lower apart from their group 17 and 16
S (solid) and Cl (larger enthalpy of atomisation than F bc of weak FF bond due to the side of F)

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9
Q

why does carbon have the strongest enthalpy of atomisation

A

group 14
4 valence electrons
4n electrons for 4 bonding Mo
n= number of atoms

more or less e- = fewer bonding or more antibonding filled

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10
Q

group 14
state, bond length, shape, hybrid

A

solids at room temp
bond length increases down the group
tetrahedral 109.5 (tetravalent)
sp3 hybrids

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11
Q

allotrope meaning

A

different physical form of an element
carbon + graphite (most stable)
carbon + diamond (not most stable)

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12
Q

graphite carbon allotrope

A

most stable carbon allotrope
hexagonal layers of sp2
slanted hexagonal layers (ababab)
e- delocalised into pi orbital (double bond character)

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13
Q

all the carbon allotropes

A

diamond
graphite
graphene
fullerenes

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14
Q

diamond allotrope

A

each c is tetravalent
sp3 hybridised
not most stable allotrope
tetrahedral shape of C
109.5 *

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15
Q

graphite allotrope

A

Sp2 hybridised carbon
1e- delocalised into Pi orbital
double bond character
layers of hexagonal planes slanted
ababab shape
hexagonal layers most stable allotrope

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16
Q

graphene C allotrope

A

one single layer of graphite
1 hexagonal layer

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17
Q

fullerene C allotrope

A

a graphene layer but rolled up into a cylinder

closed sheet of graphene
sheet of hexagons and pentagons (allow bending)
sheet is wrapped around and joined up

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18
Q

Sn tin allotrope

A

white tin
beta tin
distorted octagonal array
stable at room temp
metal
more e- are delocalised than graphite

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19
Q

lead allotrope

A

metallic fcc
only forms metallic structures
closed pack structure

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20
Q

group 14 and bond strength

A

4 valence electrons make the bond strength large

can fill the MO

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21
Q

group 15

A

5 valence : 2* 3 bonding
N is gas at room temp, rest are solids
each has rhombohedral allotrope
( fused cyclohexane chairs with lone pair, tetrahedral shape, hexagonal layers) : black P, alpha As, alpha Sb, alpha Bi.
bond length increases down the group
weaker bonds (bonded to 3 not 4)

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22
Q

group 15, white phosphorus structure

A

tetrahedral shape
lone pair on each phosphorus
3 bonds per P.

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23
Q

anything group 15 has how many bonds

A

3 BONDS
1 lone pair!!!
tetrahedral shape

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24
Q

group 16 has how many valence electrons

A

6!!

can only form 2 BONDS
2 LONE PAIRS
per atom.

2 single bonds per atom

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25
Q

group 16 S8 crown

A

crown shape
2 bonds each
daisy crown of 8 S elements

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26
Q

group 16 helical element

A

single helix (like dna)
2 bonds - chain
2 lone pairs each
atom with bunny ears chain
lower atom as only 2 bonds need to break

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27
Q

why do group 14 have highest enthalpy of atomisation

A

4 bonds must be broken (all bonding e-)

28
Q

why does group 15 have a lower enthalpy of atomisation than group 14

A

3 bonding
1 lone

easier to break 3 bonds than 4

29
Q

why does group 16 have a lower enthalpy of atomisation than 14 and 15

A

2 bonds
2 lone pairs
per atom.

easier to break 2 bonds than 4 or 3

30
Q

group 17

A

dimers!!
only 1 bonding electron left
single bond
3 lone pairs
F2 Cl2 Br2 etc

31
Q

down group 17melting and bp

A

melting point and boiling point increases

increase in VDW as atomic weight increases

32
Q

F2 colour

A

colourless

33
Q

Cl2 colour

A

yellow green

Clover: yellow (gold) green (leprechauns)

34
Q

Br2 colour

A

red brown liquid

Breens 🫘:red brown liquid

35
Q

I2 colour

A

purple / black solid

Indigo (dark black purple)

36
Q

group 18

A

noble gases
held together via VDW
low melting + bp.
m + bp increase down the group
monoatomic gases
5K liquid range between bp+mp (must keep temp very constant)

37
Q

group 18 weight

A

heavier down the group
atomic radius increases
greater VDW attractions

38
Q

group 18 has the

A

highest ionisation energies
but Xe and O have similar ionisation energies
u can ionise O2 into O2+ with strong oxidising agent so u can do it with Xe aswell (PtCl6 = oxi agent)

39
Q

homonuclear bonds

A

bonds between 2 atoms of the same element

40
Q

small elements have stronger bonds, why is this

A

smaller element = greater effective overlap = stronger bond

41
Q

N-N O-O F-F are weaker than expected bc what

A

they’re small
repulsion causes a weaker bond

significant interaction repulsion bc of their small size

42
Q

down the group what happens to bond strength

A

decreases
diffuse orbitals
less effective overlap
weaker bond

43
Q

are sigma or pi stronger (not for N or O) but generally

A

sigma
overlap
point towards eachother (pz are directional)

pi = less effective overlap, non directional, weaker than sigma bond (side side interactions)

44
Q

why are pi bonds better for N and O

A

small atoms, sigma bonds are weak due to inter atomic repulsion’s due to their small size.

pi bonds allow side side interactions allowing for pi bonds to be stronger than sigma bonds for N and O. DOUBLE BONDS ARE PREFERED

45
Q

what is the favoured bond

A

bond with most energy
aka strongest bond
N = triple bond!! bc x3 single bond is still smaller than a triple bond

46
Q

why is N a gas

A

it’s energetically favoured by the element
forms triple bonds bc the triple bond is the strongest (most favoured)

47
Q

heteronuclear bonds

A

bonds between two different atoms

48
Q

what is the strength of heteronuclear bonds determined by

A

difference in electronegativity
more polar = more electronegativity difference = more ionic character = stronger bond

pauling and his electronegativity

49
Q

oxidation state definition

A

the charge the atom would have if a more electronegative atom bonded to it and acquired all the electrons

NF3 ( N= +3. F= -1)

50
Q

valency definition

A

max number of univalent (1bond) atoms that can combine with an atom of another element under consideration

eg: trivalent, monovalent , connected to 3 or 1 different things.

51
Q

hyper valent

A

main group elements (period 2 ns2 np6) that have more than 8e- in their valence shell
PF5 PCl5 etc etc!! 10e- in their valence shell not 8e- 😮😮😮😮

52
Q

inert pair effect

A

when the valence S electrons don’t take part in bonding.
oxidation state is 2 less than group valency.

group 13 = +3 oxi state, TI group 3 = +1 oxi state

53
Q

higher than expected ionisation energy of an atom means it’s bond strength when bonded to smt else is

A

weaker ??

54
Q

lewis acid

A

electron pair acceptor
accepts electrons in the LUMO
acids accept
electrophile

55
Q

lewis base

A

electron pair donor
FROM HOMO
nucleophile

56
Q

brønsted-lowry acid

A

donates protons H+

57
Q

brønsted-lowry base

A

accepts protons H+

58
Q

brønsted-lowry lowry is based on the movement of

A

protons

59
Q

lewis theory involves the transfer of

A

electron pairs.

60
Q

if lewis acids accept electron pairs they must have

A

empty p orbitals
LUMO

group 13 have an empty p orbital

61
Q

what are frustrated lewis pairs

A

bulky lewis acids and bases
cannot form addicts due to steric hinderance
e- can’t get close enough
they rip apart lewis acids and bases

62
Q

how do double pairs affect VSEPR theory

A

they dont effect the shape of the molecule by changing the amount of e- pairs around the central atom. this is bc they have the same direction as a single bond. there is a sigma bond in a pi bond

they change the bond angles due to more repulsion, double bond is shorter, closer to nuc, more repulsion

63
Q

in trigonal bipyramidal, how many nmr environents can there be

A

2, for axial and equitorial bc theyre of different energies + environments

64
Q

molecular shape fluxionality

A

when the shape of a molecule is not rigid, atoms can move as bonds stretch or vibrate. if the energy is small enough, the molecule can change shapes rapidly (interconvert)

trigonal bipyramidal to square planar ( 4 - 1 - 1 )

65
Q

berry pseudorotation

A

type of vibration that causes a molecule to isomerise by exchanging ligand position (axial –> equitorial,,, equitorial –> axial)

the groups move internally, they arent rotated.

happens so fast an average of both is seen by nor.

inorganic sem1 (13 decks)

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