By: Ellis Martin

Physical Properties of Molybdenum

Atomic Mass: 95.94

Atomic Radius: 190pm

Density: 10.280 g/cc

Melting Point: 2623° C

Boiling Point: 4639°

At room temperature (22°C), this element is a: Solid

Appearance: Looks like Steel, shiny gray, a high strength alloy

Conductivity: Able to conduct heat and electricity

Malleability: Is malleable, not brittle

Hardness: Very hard

Other physical properties: Has a very high melting point and a very high boiling point

Chemical Properties of Molybdenum

Flammability: It is flammable in the form of powder or dust

Reactivity: Doesn’t react to air, oxygen, or water, not very reactive

Identifying Information

Atomic Structure

Atomic Number: 42

Mass Number: 95.94

Protons: 42 protons

Neutrons: 54 neutrons

Electrons: 42 electrons

Location on the Periodic Table

Around the left center of the periodic table. It is the 42 element listed.

History and Discovery

When was your element discovered (or first produced if it is manmade)?

Molybdenum was found in 1778

Where was your element discovered (or first produced if it is manmade)?

Molybdenum was discovered in molybdenite, in a Swedish lab

Who first discovered (or first produced if it is manmade) your element?

Molybdenum was discovered by Carl Welhelm Scheele

Why/how was your element discovered (or produced if it is manmade)?

Molybdenum was chemically separated from a mineral known as molybdenite by

Peter Jacob Hjelm in 1781.

Applications and Uses

In what ways is your element most commonly used? Where is your element most often


The metal is used to make some missile and aircraft parts and is used in the nuclear power industry. Used in high grade steel alloys. It is most commonly found in molybdenite.

What specific isotopes of your element have unique or important uses or applications?

There are 33 known isotpoes of molybdenum ranging from 83 to 115 in atomic mass. Seven isotopes occur naturally, with atomic masses of 92, 94, 95, 96, 97, 98, and 100.

Does your element form specific compounds (or alloys) that have important uses?

High grade steel alloys. Used to make strong things and things that need a high melting point. It is used for roads, railways, other infrastructure, appliances, and buildings.

Molybdenum (element #42)

Name and Symbol

Where does your element’s name and/or symbol come from? Any interesting stories there?

The name comes from the mineral molybdenite that it was found in and the symbol Mo comes from the first two letters of molybdenum.

Sources Used

Element Card: Gray, Theodore W. (2008). The Photographic Card Deck of the Elements.

Elements Book: Gray, Theodore W. (2009). The Elements: A visual exploration of every known atom in the universe. New York: Black Dog & Leventhal Publishers, Inc.

Jefferson Lab Periodic Table:

Peter Jacob Hjelm:

Carl Willhelm Scheele: