Magnesium, with its atomic number 12 and chemical symbol Mg, is a metallic element renowned for its silvery-white luster. It is found in nature as a bountiful constituent of the Earth’s crust, participating in a multitude of chemical compounds and alloys.
Rubidium, on the other hand, is quite an enigmatic element. Occupying position 37 on the periodic table with the symbol Rb, it is a silvery-white metal with a distinctive pinkish hue. In stark contrast to the abundance of magnesium, rubidium is considered a rather scarce element in the Earth’s crust.
These are the key differences between magnesium and rubidium below:
| Magnesium | Rubidium |
| Magnesium is a silver-white, lustrous metal with a reflective surface. | Rubidium is a silvery-white metal with a distinctive pinkish tint. |
| This has a low density of approximately 1.74 g/cm³. | It is denser than magnesium, with a density of about 1.53 g/cm³. |
| Magnesium has relatively low melting (650°C) and boiling (1,090°C) points. | Rubidium has an exceptionally low melting point (39.3°C) and boils at approximately 688°C. |
| Magnesium exhibits good malleability and ductility, allowing it to be shaped and drawn into various forms. | Rubidium is soft and malleable, allowing it to be cut with a knife. |
| It is moderately reactive, forming a protective oxide layer when exposed to air and reacting with acids. | It is highly reactive, readily reacting with air, moisture, and water. |
| Magnesium burns with an intense white flame when ignited, making it valuable in flares and fireworks. | Rubidium is extremely flammable and must be handled with great care. |
| Magnesium is corrosion-resistant, especially when properly treated and alloyed. | Rubidium is highly susceptible to corrosion due to its reactivity. |
| It is highly electropositive, readily donating electrons in chemical reactions. | Rubidium exhibits high electropositivity, making it valuable in chemical processes and as a source of electrons in batteries. |
| Magnesium is a relatively hard metal. | It is a soft and malleable metal. |
| Magnesium is used in alloys, construction materials, fire retardants, and dietary supplements. | Rubidium is employed in atomic clocks, vapor lamps, photocells, lasers, and as a catalyst in various chemical processes. |
Magnesium: A Study in Lightness
Physical Properties
- Magnesium is a silver-white, lustrous metal with a reflective surface. Its appearance is characterized by a metallic sheen.
- Magnesium is known for its low density, making it one of the lightest structural metals. It is approximately 1.74 grams per cubic centimeter (g/cm³).
- Magnesium’s melting point is relatively low at 650 degrees Celsius (1,202 degrees Fahrenheit), while its boiling point is approximately 1,090 degrees Celsius (1,994 degrees Fahrenheit).
- It exhibits good malleability, meaning it can be hammered into thin sheets, and ductility, allowing it to be drawn into wire.
Chemical Properties
- Magnesium is moderately reactive. It readily reacts with oxygen to form a protective oxide layer on its surface, which prevents further corrosion. It also reacts with acids, releasing hydrogen gas.
- When ignited, magnesium burns with an intense and brilliant white flame, making it a valuable component in flares and fireworks.
- Magnesium is corrosion-resistant, especially when properly treated and alloyed. It is used in various applications that require resistance to corrosion.
- Magnesium is highly electropositive, meaning it readily donates electrons in chemical reactions, making it a valuable element in electrochemical processes and batteries.
Rubidium: The Pinkish Alkali Metal
Physical Properties
- Rubidium is a silvery-white metal, but what sets it apart is a distinctive pinkish tint, giving it a unique visual signature.
- Rubidium is considerably denser than magnesium, with a density of approximately 1.53 g/cm³.
- Rubidium’s melting point is exceptionally low at just 39.3 degrees Celsius (102.7 degrees Fahrenheit), and it boils at approximately 688 degrees Celsius (1,270 degrees Fahrenheit).
- Rubidium is a soft and malleable metal that can be easily cut with a knife, which is uncommon for metals.
Chemical Properties
- Rubidium is highly reactive, even more so than other alkali metals. It reacts vigorously with air, moisture, and water. When exposed to air, it can spontaneously ignite.
- Due to its reactivity, rubidium is extremely flammable, and it must be handled with great care in controlled environments.
- Like other alkali metals, rubidium exhibits high electropositivity, making it valuable in chemical processes and as a source of electrons in batteries.
- Rubidium’s electronic transitions have made it an essential component in atomic clocks, which are highly precise timekeeping instruments.
Applications
Magnesium
- Magnesium alloys are used in the production of lightweight materials for automotive and aerospace industries.
- Its oxide is used in the production of building materials such as cement and concrete.
- Magnesium compounds are used in fertilizers, medicines, and detergents.
- Magnesium hydroxide is used as a fire retardant in plastics, paint, and insulation materials.
- It is an essential mineral for human nutrition, and magnesium supplements are used to treat magnesium deficiency.
Rubidium
- Rubidium atomic clocks are used to maintain precise timekeeping.
- Its vapor lamps are used in streetlights and industrial lighting.
- Rubidium photocells are used in optical switching devices and solar cells.
- Rubidium lasers are used in spectroscopy and precision measuring instruments.
- They are used in organic synthesis and polymerization reactions.
Key Takeaways
Concepts Berg
What is magnesium, and where is it commonly found?
Magnesium is a chemical element found in the Earth’s crust and is the eighth most abundant element in the universe.
What are the physical properties of magnesium that make it unique?
Magnesium is known for its low density, high malleability, and corrosion resistance.
Why is magnesium used in alloys, and what are some common alloy applications?
Magnesium is used to make lightweight and strong alloys, which find applications in aerospace, automotive, and structural materials.
How does magnesium contribute to fire safety, and in what forms is it used as a fire retardant?
Magnesium serves as a fire retardant by slowing down combustion. It’s used in fire extinguishers and fireproof materials.
Why is magnesium an essential nutrient in human nutrition, and where is it commonly found in our diets?
Magnesium is vital for various biochemical processes in the body and is found in foods like leafy greens, nuts, and whole grains.
What is rubidium, and where is it typically found?
Rubidium is a chemical element present in trace amounts in Earth’s crust and is often associated with potassium minerals.
What distinguishes rubidium’s appearance from other metals?
Rubidium is a silvery-white metal but exhibits a unique pinkish tint, setting it apart from other elements.
Why is rubidium used in atomic clocks, and how does it contribute to precise timekeeping?
Rubidium’s electronic transitions are used in atomic clocks to provide highly accurate time measurements.
In what industries and applications is rubidium vapor used, and what are its distinct properties for these uses?
Rubidium vapor is employed in fields such as lighting (vapor lamps) and lasers, known for their unique spectra.
