CHE 2C - CH. 19 Transition Metals

Transition metals exhibit ____

metallic luster and high electrical and thermal conductivities

When forming ionic compounds, the cations are often ______

complex ions

Ligands

molecules or ions that behave as lewis base

Paramagnetic

electrons are unpaired

Transition metal ions show that 3d orbitals have ______ then 4s orbitals

less energy

• the electron that remains when an ion is formed is from the 3d orbital

Higher OS are not seen for the first row due to 3d orbital’s _____

lower energy

• increased nuclear charge, causing electrons to be difficult to remove

Metals with the most _____ are the best ________

positive potentials, reducing agents

Reducing Abilities of the first row _____

decrease left to right

The Lanthanide Contraction

2nd and 3rd row radii are the same due to poor shielding from the f-electrons thus reducing the radii in the 3rd row

Half filled and Completely Filled Shells of d-Orbital

Cr, Cu, Mo, Ag

Coordination Compounds

usually colored and paramagnetic; consists of a complex ion

Complex Ion

TM ion w/ attached ligands and the counter ion to produce a compounds with no net charge

Coordination Number

the number of bonds/ligands around the central metal atom

• 6 is the most common

Lewis Base

electron pair donor

Lewis Acid

electron pair acceptor

A ligand will ____ an electron pair to an empty orbital on a metal ion

donate

Monodentate

ligand can form one bond to a metal ion

Bidentate

a ligand that forms 2 bonds to a metal ion

• ethylenediamine (en)

Polydentate

ligand that forms more than 2 bonds to a metal

• EDTA

Fluorine

Fluoro

Chlorine

Chloro

Hydroxide

Hydroxo

Cyanide

Cyano

H2O

aqua

NH3

ammine

CO

Carbonyl

No

Nitrosyl

When naming complex compounds, how are the ligands named?

in alphabetical order

When is the latin elemental name used?

when the metal is in the anion

• the compounds is bimetallic

Iron Fe

Ferrate

Copper Cu

Cuprate

Lead Pb

Plumbate

Silver Ag

Argentate

Gold Au

Aurate

Tin Sn

Stannate

Isomers

when 2 or more species have the same formula but exhibit different properties

Structural isomers

contains the same atoms but one or more bonds differ

• linkage isomer

• coordinate isomer

stereroisomerism

all bonds are the same but the spatial arrangement of atoms are different

Geometric Isomers

Cis (close together) and Trans (across from each other)

Optical isomers

have opposite effects on plane polarized light

Optical Activity

exhibited by molecules that have a nonsuperimposable mirror image

• they are chiral

Chiral

objects that are optically active and are nonsuperimposable

Counter Ion

anion or cation needed to produce a compound w/ no net charge

Enantiomers

group of isomers that are nonsuperimposable

Linkage Isomer

same composition, different points of attachment

Coordinate Isomer

composition of the complex ion varies; switch of coordinate and counter ion

Dextrorotatory (d)

isomer that rotates the plane of light to the right

Levorotatory (l)

isomer that roates the plane of light to the left

Racemic Mixture

does not rotate the plane of the polarized light; the two opposite effects cancel

The Crystal Fields Model

color and magnetism of complex ions result from changes in the energies of the metal ion d-orbital caused by metal-ligand interactions

Definition of the Crystal Fields Model

assumes that ligands can be approximately by negative point charges and that metal-ligand bonding is entirely ionic

Strong field

large splitting - low spin

• lower energy orbitals pair up before filling the upper energy

Weak Field

small splitting - high spin

• electrons pair singly in each orbital before pairing up

Spetrochemical Series

list of ligands based on their abaility to produce d-orbital splitting

• CN- strong field

• I- weak field

The magnitude of delta ______ as charge of the metal ion increases

increases

Tetrahedral Splitting

4/9 smaller than octahedral

Due to small splitting, tetrahedrals are always what?

they are always high spin-weak field

Molecular Orbital Model

1. extent of overlap

2. relative orbital energies

Extent of Overlap in the MO Model

ligands pointing directly towards the metal are more involved

Relative Orbital Energies in the MOD Model

AOs that are close in energy will interact more strongly than those widely apart in energy

Which metals assume a square planar geometric with either 2+ or 3+ OS?

metals in Group 10 and Group 11

Whats the difference between a metal oxides and nonmetal oxides?

• metal oxides: basic

• nonmetal oxides: acidic

Amphoteric compounds

Al2O3 and BeO

density pattern

increases then decreases across the d-block

• 3rd row has a higher density due to the Lanthanide contraction

trans/mer octahedrals

achiral

4 or more of the same ligands

achiral

2 or more of the same ligands

achiral

CFM Square Planar

CFM Linear