inorganic chem - rias flashcards

< 0.225

coordination = 3, shape = trigonal planar

0.225-0.413

coordination= 4, shape = tetrahedral

0.414-0.731

coordination=6, shape = octahedral

0.732-0.999

coordination = 8, shape = cubic

1

coordination = 12, shape = close packed structure

cubic

a=b=c α=β=γ=90

hexagonal unit cell

a=b≠c α=β=90 γ=120

HCP

coordination number = 12, but TAKE INTO ACCOUNT OCTAHEDRAL HOLES

how many nodes does a 4f orbital have?

3 nodal planes, 0 radial nodes

higher oxidation states mean…….

more electronegative

elements with lower electronegativity….

mean more metallic

which is stronger - I-CL or I-BR

I-CL

is ethane thermodynamically unstable at room temp and pressure?

yes

is ethane kinetic stable at room temp and pressure?

yes

1st ionisation energies- what accounts for difference in values

due to differences in their electron configuration and differences in their relative Zeff

if atoms are the same…..

equal repulsion so no distortion so have the same bond angles

corners =

x 1/8

middle =

x1

edges =

x 1/4

n for born- lande

he = 5, ne=7,ar=9,kr=10,xe=12

radius ratio for an octahedral hole

square root 2a = 4r

ka x kb =

kw

which is stronger? bbr3 or bcl3

bcl3

how many nodes does a 4s orbital have?

3

how many pi symmetry in co2?

4

how many nodes does a 5f orbital possess?

1 radial node and 3 nodal planes

explain the reactivity of F2 molecule?

1. heteronuclear bonds containing F tend to be strong, F is relatively small 3. the f-f bond is weakened by lone pair to lone pair repulsions 4. the f-f bond has a relatively large populatioin of electrons in pi antibonding orbitals

down a group, eg for group 1 + 2 elements - ca2+ is larger than mg2+ due to…..

increasing n

what is the henderson hasselbach equation?

pH = pKa + log [A-]/[HA]

what is additional pi- back bonding?

the donation of electron density from a metal's d-orbitals into a ligand's π* anti-bonding orbital. This process can strengthen the metal-ligand bond and alter the ligand's properties

what is the packing density of the BCC structure?

68 %

zinc blende structure and coordination number

tetrahedral and coordination 4

what is the bond order and magnetism for hf?

BOND ORDER IS 1 AND IS DIAMAGNETIC and the sigma MO has more F character than H. The lowest unoccupied molecular orbital is sigma antibonding

how many nodes does a 4d orbital have?

3 in total - 1 radial node and 2 nodal planes

which boiling point is higher? H20 or H2S

H20

What is the structure and coordination number of NiAs?

octahedral and 6

what is the structure and coordination number of nacl?

octahedral and 6

what is the structure and coordination number of ZnS(wurtzite)?

tetrahedral and 4

what is the structure and coordination number of CsCl?

8 coordination number

what is the order of increasing packing density within a unit cell?

smallest: primitive cubic

next: body centred cubic

biggest: hexagonal close packed = cubic close packed

bond length nacl

a/2

what is radial distribution function?

probability of finding an electron at a distance r from the nucleus

describe the trend in atomic radius?

atomic radii down a group increases due to increasing n. For example, C to Si follows trend in increasing due to higher n, but Si to Ge shows a very slight increase as the Ge valence now contains poorly shielded d - orbital. This increases Z eff to almost overcome the increasing n. Pb also follows this as is contains poorly shielding f- orbitals and this is enough to allow z eff to overcome increasing n.

what does born mayer assume?

born mayer assumes perfect ionic bonding- but compounds may have partial covalent character which lowers the lattcie energy

why does electronegativity decrease down a group?

due to the z eff number and increasing n. The atomic radius increases, due to additional electron shells. This increases the distance between the nucleus and outer shell electrons, reducing nuclear attraction.The nuclear charge increases down a group, the effect is mostly offset by shielding, ( introduction of s,p,f orbitals) so the effective nuclear charge felt by valence electrons does not increase significantly, furthur reducing electronegativity

explain why z eff increases across a period?

z increases, which increases the nuclear charge. electrons are added to the same shell so they are all the same distance from the nucleus.

degrees of shielding power?

s orbitals shield the most effectively, followed by p-orbitals, then d-orbitals and then f-orbitals

what is the atomic radius?

it is half the distance between the centres of neighbouring atoms in a solid or for non metals, in a homonuclear molecule( eg o2 or p4)

what happens to atomic radius across a period?

it decreases as the nuclear charge increases

what happens to atomic radius down a group?

it increases down a group which shows that the valence shell (n) ( principle quantum number) which the outer electrons occupy is more important than z eff

What is the ionic radius?

It is derived from the distance between the centres of adjacent ions in a crystal, as determined using x-ray diffraction studies

What happens to the ionic radii across a period?

the nuclear charge increases, at the same time the positive/ negative charge carried by the element increases eg from +1 to +3. The remaining electrons feel an increasing zeff and are drawn closer to the nucleus. The ions decrease in size

what happens to the ionic radii down a group?

it increases

what is the ionisation energy?

It is the energy required to remove one mole of electrons from one mole of a gaseous species in their ground( or standard) state.

what happens to ionisation energy across a period?

it increases across a period, z eff increases, atomic radii decreases

what happens to ionisation down a group?

it decreases down a group due to the principal quantum number increasing

what is electronegativity?

it is the ability of an atom in a molecule to attract electrons to itself

what happens to electronegativity across a period?

it increases across a period, reflecting increasing z eff

what happens to electronegativity down a group?

it decreases down a group, reflecting increasing n

what is electron affinity?

it is the energy released when one mole of electrons is added to 1 mole of gaseous atoms in their ground ( or standard state). Ea is +ve for an exothermic reaction ea is -ve for an endothermic reaction

what happens to electron affinity across a period?

it increases across a period due to increasign z eff and decreasing atomic radii.

diamagnetic

no unpaired electrons

paramagnetic

unpaired electrons

how to find bond order?

number of bonding - number of anti-bonding / 2

what is lewis theory?

it is only valence electros that are important in the making of covalent bonds

what is bond energy?

it is the amount of energy required to break a bond into neutral atoms

the larger the bond energy…….

the stronger the bond

as you go down the group bond energy…..

gets weaker

order of halogen bonding

C-F > C-CL> C-BR

What is catenation?

When elements prefer to form lots of single bonds, generating polymer-like structures. The occurs when homonuclear pi bonds are weak

pi > sigma means?

more likely to form double bonds and be MOLECULAR

sigma> pi means?

more likely to fotm catenated single bonds and be POLYMERIC

what is a crystalline solid?

those in which the atoms or ions are in an orderly array called a lattice eg nacl or diamond

What is an amorphous solid?

those in which the atoms or ions lie in a random jumble eg rubber or glass or amorphous si02

radius ratio for a tetrahedral hole?

square root 2 x L = 2R

what does BORN LANDE not take into consideration?

NO CONSIDERATION OF REPULSION OR COVALENCY

what does BORN MAYER not take into consideration?

COVALENCY

Lewis acid

electron pair acceptor

lewis base

electron pair donor

paulings rule for oxoacids firast deprotonation

pka1 = 5-5x ( x is number of oxo groups)

Second deprotonation

pka2= pka1 + 5

Madelung constant (A)

1.7476

HCP packing density

74%

Why are heteronuclear bonds often stronger?

A bigger difference in electronegativity leads to a strongerbond

No electronegativity differences in homonuclear bondse.g.

electron promotion energy

An s-electron is promoted to a p-orbital. This requires energy