12 Mg Magnesium 24.305 u

Magnesium

Add one script tag to your page:

<div data-chemfyi="element" data-slug="Mg"></div>
<script src="https://cdn.jsdelivr.net/npm/chemfyi-embed@1/dist/embed.min.js" defer></script>

Embed as an iframe:

<iframe src="https://chemfyi.com/iframe/element/Mg/?style=modern&theme=light" width="420" height="400" frameborder="0" loading="lazy" style="border:0;border-radius:10px;max-width:100%"></iframe>

Paste the URL in WordPress, Medium, or Ghost:

https://chemfyi.com/element/mg/

Shields.io-compatible SVG badge:

Magnesium badge ![Magnesium](https://chemfyi.com/badge/element/Mg.svg)

Web Component:

<chemfyi-element slug="Mg"></chemfyi-element>
<script src="https://cdn.jsdelivr.net/npm/chemfyi-embed@1/dist/embed.min.js" defer></script>
Period
3
Group
2
Block
s-block
Phase (STP)
Solid

Magnesium is a lightweight alkaline earth metal essential for living cells. It burns with a bright white flame and is used in alloys and fireworks.

Appearance: Shiny grey solid

About Magnesium

Recognized as containing a distinct element by Joseph Black in 1755, magnesium is a lightweight alkaline earth metal with atomic number 12 and an atomic mass of 24.305. Its density of 1.74 g/cm³ places it among the lightest structural metals, and it melts at 923 K. Two valence electrons ([Ne] 3s2) yield an electronegativity of 1.31 and a first ionization energy of 738 kJ/mol. Magnesium is essential to living cells. The metal burns with a brilliant white light, a property exploited in fireworks, while its low density makes it valuable in alloys. It occupies group 2, period 3, directly below beryllium.

Physical Properties

Atomic Mass 24.305 u
Density 1.738 g/cm³
Melting Point 649.9 °C
Boiling Point 1089.8 °C
Phase at STP Solid
Atomic Radius 145.0 pm

Electronic Properties

Electronegativity 1.31
Ionization Energy 737.7 eV
Valence Electrons 2

Electron Configuration

Configuration [Ne] 3s²

Electron Shell Configuration

Magnesium electron shell configuration Mg 2e⁻ 8e⁻ 2e⁻
Electron shell structure of Magnesium — electrons per shell.
Shell Electrons
1 (K) 2
2 (L) 8
3 (M) 2

Position in Periodic Table

Magnesium position in the periodic table Mg

Discovery

Discovered by: Joseph Black
Year: 1755

Block & Period

Block

s p d f

Period

1 2 3 4 5 6 7

Periodic Table

Lanthanides Actinides

Reactions Involving Mg

Displacement of Hydrogen from Acid by Magnesium

Mg + 2HCl → MgCl₂ + H₂

Redox

Formation of Magnesium Oxide

2Mg + O₂ → 2MgO

Synthesis

Magnesium Hydroxide and Hydrochloric Acid (Antacid)

Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O

Double-Replacement

Magnesium Hydroxide and Hydrochloric Acid (Milk of Magnesia)

Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O

Acid-Base

Magnesium Hydroxide Precipitation

MgCl₂ + 2NaOH → Mg(OH)₂↓ + 2NaCl

Precipitation
View all 10 reactions →

Compounds Containing Magnesium

Magnesium Carbonate

MgCO₃

Magnesium Chloride

MgCl₂

Magnesium Hydroxide

Mg(OH)₂

Magnesium Oxide

MgO

Magnesium Silicate

Mg₃Si₄O₁₀(OH)₂

Magnesium Sulfate

MgSO₄

Talc

Mg₃Si₄O₁₀(OH)₂

More Alkaline Earth Metal

4 Be Beryllium 20 Ca Calcium 38 Sr Strontium 56 Ba Barium 88 Ra Radium

Explore on Science FYI

MineralFYI
Dolomite

Calcium magnesium carbonate mineral

Frequently Asked Questions

What is Magnesium?
Magnesium (Mg) is a chemical element with atomic number 12. It is a solid at standard temperature and pressure, classified as a alkaline earth metal.
What are the key properties of Magnesium?
Magnesium has an atomic mass of 24.305 u, density of 1.738 g/cm³, melting point of 649.9°C, boiling point of 1089.8°C.
What is the electron configuration of Magnesium?
The electron configuration of Magnesium is [Ne] 3s2. It is in the s-block of the periodic table.
Who discovered Magnesium?
Magnesium was discovered by Joseph Black in 1755.
What is the electronegativity of Magnesium?
Magnesium has an electronegativity of 1.31 on the Pauling scale.