Molybdenum

TRANSITION METAL

Bohr Model: Electrons arranged in energy shells around the nucleus.

Molybdenum is a chemical element with symbol Mo and atomic number 42. The name is from Neo-Latin molybdaenum, from Ancient Greek Μόλυβδος molybdos, meaning lead, since its ores were confused with lead ores. Molybdenum minerals have been known throughout history, but the element was discovered (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele.

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Quick Facts

Atomic Number 42

Period 5

Group 6

Phase Solid

Appearance gray metallic

About Transition Metals

Transition metals are elements with partially filled d-orbitals. They are hard, have high melting points, and often form colored compounds.

History

Discovered By Carl Wilhelm Scheele

Named By Unknown

Physical Properties

Atomic Mass 95.951

Density 10.28 g/L

Molar Heat 24.06 J/(mol·K)

Phase Transition (Melting & Boiling Points)

Molybdenum melts at 2896 K and boils at 4912 K.

Atomic Properties

Electron Config [Kr] 4d5 5s1

Electronegativity 2.16

Electron Affinity 72.1 kJ/mol

Ionization Energy 684.3 kJ/mol

Orbital Filling Diagram

This diagram visualizes electron configuration according to the Aufbau principle and Hund's rule. Boxes represent orbitals (s, p, d, f), while arrows indicate electrons with spin up or down. Electrons fill lower energy levels first and occupy orbitals singly before pairing.

Photograph

Source: Wikipedia

External Resources

Wikipedia PubChem Royal Society of Chemistry Periodic Videos (YouTube)

Study Guide

Atomic Number

The number of protons in the nucleus, which defines the element.

Atomic Mass

The average mass of an atom, including protons and neutrons.

Electronegativity

A measure of how strongly an atom attracts electrons in a bond.

Ionization Energy

The energy required to remove an electron from an atom.

Electron Config

The arrangement of electrons in the atom's energy shells.