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12 Mg Magnesium 24.305

Magnesium

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

Magnesium is a chemical element with symbol Mg and atomic number 12. It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column (Group 2, or alkaline earth metals) of the periodic table:they each have the same electron configuration in their outer electron shell producing a similar crystal structure. Magnesium is the ninth most abundant element in the universe.

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Quick Facts

Atomic Number 12
Period 3
Group 2
Phase Solid
Appearance shiny grey solid
About Alkaline Earth Metals

Alkaline earth metals (Group 2) are reactive metals, though less so than alkali metals. They typically lose two electrons to form cations with a +2 charge.

History

Discovered By Joseph Black
Named By Unknown

Physical Properties

Atomic Mass 24.305
Density 1.738 g/L
Molar Heat 24.869 J/(mol·K)
Phase Transition (Melting & Boiling Points)

Magnesium melts at 923 K and boils at 1363 K.

Atomic Properties

Electron Config [Ne] 3s2
Electronegativity 1.31
Electron Affinity -40 kJ/mol
Ionization Energy 737.7 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.
Emission Spectrum Emission spectrum of Magnesium

Photograph

Image of Magnesium 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.