Transition Metal Chemistry

Question 1

What is the Aufbau Principle?

Answer 1

The aufbau principle states that subatomic orbitals are to be filled from the lowest energy shell upwards. This means 1s is filled before 2s and so on.

Question 2

Principal quantum number (n) describes?

Answer 2

The electron shell energy e.g. the 1 in 1s or the 3 in 3p.

Question 3

The azimuthal (angular momentum) quantum number (l) describes?

Answer 3

The shape of the orbital. The highest value of this is n-1.
0 = S orbital (Spherical)
1 = P orbital (Dumbbell)
2= D orbital (Dumbbell + Ring)
3 = F orbital (Fuck knows what that looks like)

Question 4

The magnetic quantum number (ml) describes?

Answer 4

Defines the orientation of the orbital. Can be anything from l-1 to l+1.

Question 5

The spin quantum number (ms) describes?

Answer 5

Defines the spin of the electrons, is either plus or minus 1/2.

Question 6

What does the pauli exclusion principal describe?

Answer 6

Every electron must have a unique set of 4 quantum numbers.

Question 7

What are the 2 exceptions 2 the aufbau principle and why is this?

Answer 7

Chromium and copper are the exceptions to the rule. They have only one electron in the 4s subshell, this is due to the stability associated with a half filled or filled electron shell.

Question 8

Describe the trend in atomic radii across groups in the periodic table.

Answer 8

Decrease as the period is crossed.
Increase from period 4 to 5 and form 5 to 6.
Slight increase at the end of each period.

Question 9

What is the effective nuclear charge (Z*)?

Answer 9

This is the positive charge felt by the outer electrons. it is equal to the total charge of the nucleus (Z) minus the effect of shielding from the inner electrons.
Z* = Z - S where:
Z* = effective nuclear charge 
Z = Atomic number
S = Shielding

Question 10

How is shielding calculated?

Answer 10

SHielding is the sum of the values for every electron in an atom. Each core electron ( every electron from 1s to 3p) has a value of 1. Electrons in the 4s shell have no shielding value. Electrons in the 3d shell have a value of 0.35.

Question 11

How is free energy calculated?

Answer 11

dG = dH - TdS (d is delta cos there's no delta).
dG = change in free energy
dH = change in enthalpy 
T = temperature
dS = change in entropy

Question 12

Hess’s law describes?

Answer 12

if a reaction can be written as the sum of a number of steps then the overall enthalpy change is the same as the enthalpy changes for all of the steps.

Question 13

Which element has the highest possible oxidation state and what is it?

Answer 13

Manganese

+7

Question 14

Definition of a complex?

Answer 14

Makes no fucking sense tbh.
A complex is formed when a number of ions ro molecules combine with a central metal ion to form an entity in which the number of atoms directly attached to the central metal ion exceeds the formal oxidation state of this ion.
Complexes can be anionic (negatively charged) or cationic (positively charged).

Question 15

What is the number of atoms attached to the central atom known as.

Answer 15

The coordination number.

Question 16

Describe a ligand.

Answer 16

Ligands are the molecules or ions bonded to the central metal ion. ligands bond to metal centes by donating one or more electron pairs in order to form bonds.

Question 17

describe a dative bond.

Answer 17

This is where a bond is formed using both electrons from the donor atom, the electrons are donated into an empty atomic orbital on the second atom in order to form a bond.

Question 18

What is a didentate ligand.

Answer 18

A didtentate ligand is an atom which is capable of donating two lone pairs of electrons to a metal centre. the most common is 1,2 diaminoethane (ethylenediamine). When they bond with a metal they form a 5-membered ring known as a chelate ring.

Question 19

Prefixes for naming metal ion complexes.

Answer 19

Simple Complex Number of ligands
Di Bis Two
Tri Tris Three
Tetra Tetrakis Four
Penta Pentakis Five
Hexa Hexakis Six

Question 20

Naming complex ions rules&raquo_space;

Answer 20

1. Cation is named first followed by the anion.
2. In a complex ion the ligands are named first.
3. anionic ligands end in ‘o’ e.g. bromo
4. the metal oxidation state is given directly after the metal in brackets in roman numerals.
5. the suffix ‘ate’ is added to the metal if it is the anion.

Question 21

Coordination geometry - Coordination number 2

Answer 21

Linear
180 degree bond angles, essentially a straight line.
uncommon but can be seen when ligands are very bulky.

Question 22

Coordination geometry - Coordination number 3

Answer 22

Trigonal planar geometry
ligands as far away from one another as possible
120 degree bond angles
the metal and all ligands lie on a single plane.

Question 23

Coordination geometry - Coordination number 4

Answer 23

2 possibilities: Tetrahedral or Square Planar
Tetrahedral: ligands at 190.5 degree angles
Classic shape on molecule pointing upwards the other three forming a triangle at the bottom. i.e a traingular based pyramid.
Square planar: Ligands at 90 degree angles to one another
ligands lie as far away as possible on the same plane, forming a square around the central atom.

Question 24

Coordination geometry - Coordination number 5

Answer 24

2 possibilities: Trigonal Bipyramidal or Square Pyramidal
Trigonal Bipyramidal: fuck describing that, draw it.
Square pyramidal: Essentially square planar with 4 ligands in plane and 1 pointing upwards from the cental atom at 90 degrees to the rest. looks like a squae based pyramid.

Question 25

Coordination geometry - Coordination number 6

Answer 25

Octahedral geometry:
Square planar with 2 ligands coming frommthe top and bottom of the central atom. looks like an octahedron, 2 square based pyramids pushed together basically.

Question 26

General Trends of Early transition elements

Answer 26

More susceptible to oxidation
generally form higher oxidation states
Low oxidation states are less stable.

Question 27

General trends of later transition elements.

Answer 27

Harder to oxidise
Generally form lower oxidation states.
Higher oxidation states are less stable

Question 28

What is the most common transition metal element in the Earhts crust?

Answer 28

Iron the rest are at least a 10th less abundant.

Question 29

What is the second most common?

Answer 29

Titanium

Question 30

Describe the kroll process

Answer 30

Step 1. Conversion of titanium oxide (rutile or anatase) into titanium chloride using Cl2 and C.
Step 2. Reduction of TiCl4, use magnesium as reducing agent to give Ti and 2MgCl2. run under innert atmosphere (argon) to prevent oxygen being present, burn off the MgCl to get pure Titanium.

Question 31

Name some common iron ores.

Answer 31

Haematite
Magnetite
Pyrite
Limonite

Question 32

Name some ways of preventing corrosion to iron.

Answer 32

1. Barrier methods - surface is covered wiht paint or plastic to prevent oxygen and water coming into contact with the metal.
2. Passivation -the surface is covered with a chemical layer impervious to air and moisture commonly phosphoric acid or chromium slats are used.
3. galvanisation - coat the iron with a more electropositive (less reactive) metal usually zinc, this metal is oxidised instead of the iron.