Shri. Dr. R.G. Rathod Arts and Science college, Murtizapur

Presented by, Dr. Gopalkrushna H. Murhekar

Shri Dr. R. G. Rathod Arts and Science, College Murtizapur

Study of Transition Series Elements

ALCHEMISTSAlchemist tried to make lead into gold. They studies many materials and used mysterious symbols to represent these

materials.

TRANSITION ELEMENTS

The elements in which differentiating electron enter in (n-1)d orbitals of (n-1)th main shell are called transition elements.

These elements are also known as bridge elements as they are lying between s and p bolck elements in a periodic table.

Because the differenting electron in these elements enter in d orbital so these elements are called as d-block elements.

Atomic Radius

The distance from centre of nucleus to the valence shell of electron in an atom is known as atomic radius.

Atomic radius is measured in cm. Atomic radii actually decrease across a row

in the periodic table. Due to an increase in the effective nuclear charge.

Within each group (vertical column), the atomic radius tends to increase with the atomic number number.

ATOMIC SIZE

OXIDATION STATES

VariableUp to +8 in Os & RuRe has widest range: -3 +7 !

EXPLANATION The transition metals can form a variety

of ions by losing one or more electrons. For the first five metals the maximum

possible oxidation state corresponds to the loss of all the 4s and 3d electrons.

Toward the right end of the period, maximum oxidation state are not observed, in fact 2+ ions are the most common because the 3d orbital become lower in energy as the nuclear charge increases, and the electrons become increasingly difficult to remove.

IONIZATION ENERGY Ionization energy, Ei:

minimum energy required to remove an electron from the ground state of atom (molecule) in the gas phase. M(g) + h M+ + e.

Increase across row But increase smaller than for

main-group elements Also, 3rd transition row has

higher ionization E (generally) than first 2 rows Runs counter to main-

group elements Due to outer e-’s being

held more tightly

ELECTRO NEGATIVITY

PHYSICAL PROPERTIES OF METALS

1. Efficient conduction of heat and electricity2. Malleability (they can be hammered into thin

sheets)3. Ductility (they can be pulled into wires)4. A lustrous (shiny) appearance5. All transition elements are metal at room

temperature except mercury which is liquid at room tempeture.

Platinum Sliver Gold Copper

ALLOYS

Alloys are a mixture of metals to improve strength.

Examples of alloys include: Gold jewelry (Au and

Ag)Bronze – Cu and SnBrass – Cu and ZnSterling silver – Cu

and Ag

MAGNETIC PROPERTIES

• Although an electron behaves like a tiny magnet, two electrons that are opposite in spin cancel each other. Only atoms with unpaired electrons exhibit magnetic susceptibility

• A paramagnetic substance is one that is weakly attracted by a magnetic field, usually the result of unpaired electrons.

• A diamagnetic substance is not attracted by a magnetic field generally because it has only paired electrons.

COLOR OF COMPLEX IONS

The color wheel: absorption of color appears as complementary color

Color in causes lower d-orbital e- to go up to higher d-orbital state

Specific wavelength of light kicked out

The complement of color absorbed

Colorless complexes are either d0 or d10

Don’t have d-orbital e-’s to move up

e- in partially filled d sublevel absorbs visible light

moves to slightly higher energy d orbital

Applications of Nickel

Turbine engine

ElectroplatingBatteries

TRANSITION METALS Elements in

groups 3-12 Less reactive

harder metals Includes metals

used in jewelry and construction.

Metals used “as metal.”

BRONZE Copper alloys containing tin, lead, aluminum, silicon andnickel are classified as bronzes. Cu-Sn Bronze is one of the earliest alloy to be discovered as Cu ores invariably contain Sn. Stronger than brasses with good corrosion and tensileproperties; can be cast, hot worked and cold worked. Wide range of applications: ancient Chinese cast artifacts,skateboard ball bearings, surgical and dental instruments.

COPPER The second largest use of Cu

is probably in coins. The U.S. nickel is actually

75% copper. The dime, quarter,

and half dollar coins contain 91.67% copper and the Susan B

Anthony dollar is 87.5% copper.

The various Euro coins are made of Cu-Ni, Cu-Zn-Ni or

Cu-Al-Zn- Sn alloys.

APPLICATIONS OF STAINLESS STEELS

•Stainless steels - A group of steels that contain at least 11% Cr.

Exhibits extraordinary corrosion resistance due to formation of a

very thin layer of Cr2O3 on the surface.

Categories of stainless steels: Ferrite Stainless Steels – Composed of

ferrite (BCC) Martens tic Stainless Steels – Can be

heat treated. Austenitic Stainless Steels – Austenite

() phase field is extended to room temperature. Most corrosion

resistant.

Duplex Stainless Steels – Ferrite + Austenite

Biological Importance of Iron

Plays a central role in almost all living cells.

Component of hemoglobin and myoglobin.

Involved in the electron-transport chain.

FOR YOUR ATTENTION !!!!