Introduction to Transition Metals

Question 1

transition metals are d-block elements

Answer 1

groups 3-12
low and high oxidation (3-7) states which is involved in coordination chemistry
all metals
often form coloured compounds
can be paramagnetic (magnetic) due to unpaired electrons
d-electrons cause bright colours

Question 2

atomic radii trends

Answer 2

decrease across and increase down
effective nuclear charge change or Zeff which is the net positive charge of the nucleus affects this
filled inner d orbitals shield outer s orbitals from increasing Zeff and therefore radius decreases slightly across the period

Question 3

shielding

Answer 3

cancelling out of a portion of the attraction of the nucleus to the electron due to repulsion of these electrons to each other

Question 4

Zeff

Answer 4

effective nuclear charge
involved shielding
Zeff = Z - #CE or protons in nucleus - core electrons

the electrons in the s orbital generally shield more than those in p and more than d, f and so on

Question 5

ionisation energy

Answer 5

energy required to remove 1 mol of electrons from 1 mol of atoms or ions in the gaseous state
second ionisation energy is greater than the first
low IE form cations and high form anions
as atoms increase in size, IE decreases
electronic config and stability of filled and half-filled shells changes patterns (does not increase Br to B to N to O) N Is more stable half-filled and doesn’t want to change

Question 6

electron affinity

Answer 6

energy change accompanying the addition of 1 mol of electrons to 1 mol of gaseous atoms or ions. EA1 is usually negative energy. EA2 is always positive

Question 7

electronegativity

Answer 7

atoms’ tendency to attract a bonding pair of electrons

increases across the row
decreases down a group
relatively small changes in transition metals

Question 8

atomic orbitals of transition metals

Answer 8

five-fold degenerate (equal energy) d orbitals
directional d orbitals (like p orbitals)
2 nodal planes in d orbitals (probability of finding an electron is 0)
when we form transition metal complexes, the 4s electrons drop to the 3d level eg. naked or free gases would be 4s2 3d6 but a dressed atom (with other atoms or ligands) would be 3d8 instead

Question 9

oxidations if transition metals

Answer 9

prefer to lose electrons and form cations
+2 is common because ns2 are easily lost
high ox no require a lot of energy and are rare
have a wide range of accessible and stable oxidation states in the d block

Question 10

lanthanoids

Answer 10

f orbitals have poor shielding and this causes a dramatic radius decrease
3+ oxidation states
radius decreases left to right

Question 11

general electron configurations

Answer 11

2nd row [Kr]5sx 4dy

3rd row [Xe]6sx 4f14 5dy