Transition Metals

By Daijon Rice, Jamie Elie,

Kita Hebron, Lauren Larsen &

Mekedes Mekonnen.

Background Information

Transitional elements are located in groups 3-12 on the periodic table (the d-block).

The 38 elements were discovered between the years of 1879 (Scandium) and 1996 (Unuoblum) The interesting thing about transition metals is that their valence electrons, that are used to combine with other elements are present in more than one shell.

The name transition comes from their position in the table—they form a transition between the main group elements, which occur in groups 1 and 2 on the left side, and groups 13–18 on the right.

Physical Properties of Transition

Metals

High Melting Points

High Density

High Boiling Points

High electrical

conductivity (due to

it’s loosely bound

electrons)

Physical Properties continued

Malleable and ductile

(they can be hammered

and coiled)

Metallic Luster (shiny &

polished surface)

Generally insoluble

High tensile strength

Hard/firm (solid form)

Physical Properties Continued

Most transition metal compounds are highly colored, the color of transition metals arises from a split in the energies of the d orbital's caused by coordinated molecules.

One property of transition metals is the formation of highly colored ions in solution, which leads us to our chemical properties. . . .

Learning Check (site Dr. Wilson

What is the only transitional element that

is liquid at room temperature ?

Answer

Hg !!

Chemical Properties of Transition

Metals

Forming of coloured compounds

Forming compounds with variable

oxidation states

A strong tendency to form complexes.

Useful as catalysts

Chemical Properties Continued

Transition elements

provide a wide range

of oxidation states or

positively charged

forms because they

have high electrical

conductivity and they

are very malleable.

Chemical Properties Continued

Transition metals have a tendency to form complexes (coordination compounds) this is due to their partially filled d sub-shell accepting donated electron pairs from other ions or molecules.

A complex ion is an ion containing a central atom or ion to which other atoms, ions or molecules are bonded. The atoms, ions or molecules are bonded to it with dative covalent bonds.

Chemical Properties Continued A catalyst is a substance that speeds up a chemical reaction, but is

not consumed by the reaction; hence a catalyst can be recovered chemically unchanged at the end of the reaction it has been used to speed up, or catalyze.

Transition metals and their compounds function as catalysts either because of their ability to change oxidation state or, in the case of the metals, to adsorb other substances on to their surface and activate them in the process.

Example: Formation of ammonia from nitrogen

and hydrogen using iron as the catalyst.

Fe

N2(g) + 3H2(g)--->2NH3(g)

Learning Check (sited Dr. Wilson)

What is catalyst ?

Answer

A catalyst is a substance that speeds up

a chemical reaction, but is not consumed

by the reaction.

Atomic Trends of Transition Metals

The transition metals, groups 3–12 in the periodic table, are generally characterized by partially filled d sub-shells in the free elements or their cations.

Unlike the s-block and p-block elements, the transition metals exhibit significant horizontal similarities in chemistry in addition to their vertical similarities.

Atomic Trends

The main periodic trends include:

Electron Configuration

electronegativity

ionization energy

atomic radius

melting point

metallic character

Atomic Trends Continued

Cr (chromium) and Cu (copper) are to

exception as to how the d-orbitals are

filled.

See example on the board.

Atomic Trends Continued

Transition metals have high melting/boiling points due to strong metallic bonds. Therefore, the more unpaired electrons are present, the higher the melting/boiling point will be, the first 4 elements in a row always have the highest points, as the unpaired d orbital electrons pair up, it decreases. The last 5 elements in a row have a lower melting/boiling points.

Atomic Trends Continued

Ionization energy is how much energy is

required to move one electron from an

element to the outer shell. Ionization

energy increases from left to right and

from bottom to top due to the number of

valence electrons increasing from left to

right on periodic table.

Atomic Trends Continued

The atomic radius decreases from left to right due to protons being added to the nucleus. The concentration of more protons in the nucleus creates a "higher effective nuclear charge." In other words, there is a stronger force of attraction pulling the electrons closer to the nucleus resulting in a smaller atomic radius. The atomic radius increases from top to bottom due to the increase of electrons.

Atomic Trends Continued

Metallic characteristics decrease from left to right across a period, this is caused by the decrease in radius. Metallic characteristics increase down a group, due to electron shielding which causes the atomic radius to increase thus the outer electrons ionizes more readily than electrons in smaller atoms.

Atomic Trends Continued

Electronegativity is the ability of an atom to pull electrons to itself and increases from left to rightand bottom to top. If electrons are being shared equally between atoms, the bonds will be polar, if not they will be non-polar.

Learning Check (site Dr. Wilson)

What is Electronegativity ?

Answer

Electronegativity is the ability of an atom to

pull electrons to itself.

Transition Metals in Nature

Gold, silver & copper are 3 examples of transition metals which occur in nature in a metallic state. (to the side is an example of gold (top), copper (bottom) in nature form)

Transition Metals in Industry

Gold, silver & copper

are also used in

industry. An example

is over on the side,

copper, silver, gold;

respectively.

Copper

Some other industry uses of copper: electrical wiring, build infrastructure, homes, factories, office buildings, ships, wind turbines, trains, jets and automobiles. Copper and copper-based products are also used in appliances, decorative brassware, locks and keys.

Gold

Industry uses for gold: Monetary, jewelry, art,

gold has many practical uses in dentistry

& electronics, including electric wiring & colored-

glass production.

TUNGSTEN – W

Can you recall hearing of this transition metal

before ? Most likely not, however it is a big part

of something which we all enjoy everyday.

Tungsten Continued

Tungsten, also known as wolfram, is a chemical element with symbol W and atomic number 74. The word tungsten comes from the Swedish language tung sten directly translatable to heavy stone.

W has melting point of 3,422 degree C.

Tungsten has the highest melting point of all the elements, making it ideal for use in a light bulb.

Tungsten Continued

Halogen light bulbs are a newer improved, more efficient/green light source, by adding the element Tungsten the product of the light blub was enhanced.

The light is produced by a piece of tungsten metal or filament, which shines brightly when an electrical current is passed through it. This process is called incandescence and is due to electrons becoming excited and moving through the tungsten, releasing energy as heat and light.

Tungsten Continued

Further benefits of the halogen light bulb:

reduces eye strain (due to the bright light),

illuminates details, longer lifespan (last

significantly longer than standard light

bulbs & produces more light per watt of

usage.

Tungsten Continued

When Tungsten and carbon react at high temperature makes a very hard gray compound known as Tungsten Carbide.

Tungsten Carbide is a very hard metal with a melting point of 2, 8700 degree Celsius.

It is used for wide verity of things and one of them is to make cutting and drilling tools

The following You Tube video shows how strong tungsten carbide is compared to other metals.

http://www.youtube.com/watch?v=K1P8Lp

zFbh8&feature=youtu.be

In Conclusion

Sources used:

Google images www.googleimages.com

Periodic Table: Transition Metals http://www.chemicalelements.com/groups/transition.html

ChemWiki http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Organometallic_Chemistry/Structural_Fundamentals/Periodic_Trends_of_the_Transition_Metals

How Stuff Works: Tungsten http://home.howstuffworks.com/light-bulb2.htm