transition metals

review exceptions for

chromium and copper electron configs

period 4 and 5 general atomic configs

[noble gas]ns²(n-1)d^x

period 6 and 7 (ha) general atomic configs

[noble gas]ns²(n-2)f¹⁴(n-1)d^x

when removing electrons, transition metals lose

s electrons before d electrons

tm cations with same configs have

similar properties

across a period, size of TM metals

decreases, but less than main group because the many d electrons in the inner energy level shield outer s electrons

down a group, size of TM metals

does not change significantly; adding an extra shell increases size but lanthanide contraction shrinks it

lanthanide contraction

extra protons cause a shrinkage

for period 4 transition elements, ionization energy

increases; not regular trend for period 5/6

between period 5 and 6, 

ionization energy is higher because of a higher Z_eff due to lanthanide contraction

oxidation number

charge that the atom would have if the electrons were transferred completely to/from bonded atoms

oxidation number for an atom in its elemental form

0

ON for a monoatomic ion

ion charge (sign before numeral)

sum of ON values of atoms in a molecule

0

sum of ON values of atoms in a polyatomic ion

charge of the ion

ON for groups 1 and 2 almost always

+1 and +2

ON for hydrogen

+1 when combined with nonmetals, -1 when combined with metals or boron

ON for oxygen

-2 in most cases

ON for group 17

-1 in most cases

coordination compound

behave like covalent polyatomic ions in solution (ligands remain attached)

coordination compound ions associate with

counterions to achieve neutrality

coordination compounds written inside

square brackets

coordination compound structure

transition metal center with neutral or anionic ligands

ligand

molecule or anion with one or more donor atoms, each donating a pair of electrons to the metal ion to form a coordinate bond

coordination compound illustrations

monodentate

only one bonding site

bi/polydentate

two/multiple bonding sites

coordination number

how many binding sites there are on the central metal ion; helps us figure out geometry

coordination number 2

linear geometry

coordination number 4 + d⁸ config on central metal ion

square planar

coordination number 4 + d¹⁰ or sometimes d⁵ on central metal ion

tetrahedral

coordination number 6

octahedral geometry

coordination isomer

same compound formula but different composition of the complex ion e.g. switching around ligand and counter ion

linkage isomer

same composition of the complex but the ligand donor atom is different; clue is if there is a ligand with more than one different type of atom that had a lone pair

isomerism of square planar

geometric (cis and trans)

isomerism of tetrahedral

4 different monodentate ligands can be chiral → enantiomers

naming a coordination compound

in brackets metal first, ligands next, counter ions go outside; cations first, anions second

NH₃

ammine

H₂O

aqua

NO

nitrosyl

en

ethylene diamine

CO

carbonyl

Cl^-/I^-/F^-/Br^-

chloro/iodo/fluoro/bromo

NO₂^-

nitro/nitrito

CN^-

cyano

OH^-

hydroxo

C₂O₄^2-

oxalato

number of each type of ligand indicated by

greek prefixes i.e. di, tri, tetra

if ligand already contains a greek prefix or if it is bi/polydentate then use

bis, tris, tetrakis, pentakis

ligands named in order of

alphabet, ignoring the greek prefix

roman numeral denotes

oxidation number of the central metal ion

suffix -ate is added to the metal’s name if

the complex has an overall negative charge

cation is written

before the anion

crystal field theory

as ligands begin to align themselves, the d orbitals do not remain degenerate (having the same energy)

crystal field effect

the splitting of orbitals, creating an energy difference between them, denoted as ∆

e_g orbitals

those closest to ligands, so repel the most and have higher energy

t₂g orbitals

not close to ligands, have lower energy

crystal field theory and color

electrons get excited from t2g to eg and reflects light

energy gap of the same metal depends on

ligands

strong field ligands

more electron density - more repulsion of the particular d orbitals, causing a larger difference in energy of t2g and eg, so a higher ∆

high energy in a strong field ligand →

low wavelength i.e. absorbing blue light

lower energy in a weak field ligand →

high wavelength i.e. absorbing red light

crystal field splitting energy

the energy difference between t2g and eg

spectrochemical series of ligands in order of increasing field strength

I-, Cl-, F-, HO-, H2O, SCN-, NH3, en, NO2-, NC-, CO

from d1 to d3, magnetic properties are

nonexistent because same number of unpaired electrons for strong or weak field

from d4 to d7

different properties because the excitation is different

oxidation number NH₃

0

oxidation number NO₂

0