From the Alkaline Metal Family...

By Taylor Mauldin

The Alkaline Earth Metals

We are FAMILY!

Also known as Group 2 (according to their position on the periodic table), the alkaline earth metals are unique but they share similar characteristics with the other members of the family (the other elements in group 2). The elements in this family, like group 1, are too reactive to be found in nature alone. Each element has 2 valance electrons in its highest energy level. They are harder then the Group 1 family, but softer and more lightweight than the transition metals. These elements are considered "family" because of these characteristics.

Magnesium, Calcium, and Radium

These 3 members from the Alkaline Earth Metal Family (group 2 on the periodic table) are very unique in their own way, but they share something similar; this makes them FAMILY!


Magnesium (Mg)

Atomic Number: 12

Atomic Mass: 24.3050

The first person to recognize Magnesium was an element was Joseph Black in 1755. An English chemist, Sr. Humphry Davy, was the first to "isolate" Magnesium. He did so by electrolysis of a mixture of magnesium oxide in 1808. Magnesium can be extracted from other minerals, but is more commonly found in seawater. There is approximately 1.3 billion kilograms of magnesium in every cubic kilometer of seawater (12 billion pounds per cubic mile).

Magnesium is a light, lustrous, silvery-white, metal. Capable of being shaped, Magnesium is the lightest metal that can be used to build different things. When burned, the element gives off a bright white light which is used in things such as flares, and flashbulbs for photography. However, because Magnesium burns at low temperatures, it is typically combined with aluminum. This "magnesium-aluminum alloy" makes a new material in which the physical properties of both elements balance out. In this alloy magnesium causes aluminum to be easily shaped, while aluminum causes magnesium to be stronger. The alloy created by these two elements forms a new, lightweight, yet strong, material that can be used to build things like airplanes and rockets.

The human body also needs magnesium. It is an essential mineral in the body. People who lack magnesium in their diet can take magnesium supplement pills.

There are 3 known stable isotopes of Magnesium:

Mg-24: Natural abundance 78.99%, main isotope

Mg-25: Natural abundance 10%, Used to study magnesium in the human body, used in heart disease studies

Mg-26: Natural abundance 11.01%, also used to study magnesium in the human body, also used in heart disease studies


Calcium (Ca)

Atomic Number: 20

Atomic Mass: 40.078

Discovered by Sir Humphry Davy in 1808, Calcium is a silvery metallic, malleable, metal. It is a solid at room temperature, and never found in nature all alone. Calcium is highly reactive, so it is usually found in compounds with other elements. Calcium Carbonate is one of the more common calcium compounds. Calcium carbonate is used to make chalk, white paint, toothpaste, and many other things. There are several other known calcium compounds, but there is one that is very close to the heart of humans....LITERALLY! Bones and teeth in the human body are made of calcium phosphate.

There are 6 known of Calcium, but only 3 are stable:

Ca-40(not stable): Natural Abundance 96.94%

Ca-42 and Ca-44(stable): Natural Abundance 0.647%, used in clinical research studies to measure calcium absorption in humans


Radium (Ra)

Atomic Number: 88

Atomic Mass: 226.025

Radium was discovered by Marie Curie and Pierre Curie in 1898. The two chemist made this discovery from studying a material called pitchblende, which contained uranium(also a radioactive element). They noticed that "unrefined" pitchblende was more radioactive than the uranium itself; the question "what else is in this material" probably flooded the minds of the chemist. A hypothesis was created stating "pitchblende must contain at least one other radioactive element."

The hypothesis was proven true; radium was found, and extracted, from the pitchblende. Being found as a compound enhances the fact that radium is almost never found alone in nature. It is usually found, in very small amounts, in uranium ores. In 1 ton of uranium, only about 0.14 grams of radium will be found within it. Although found in tiny amounts, radium is approximately 1,000,000,000 times more active than uranium.

Radium is silvery-white, and solid at room temperature. Due to its intense radioactivity radium, and its compounds, glows in the dark. Radium reacts very quickly with other elements; it reacts vigorously with water to form radium hydroxide, and with hydrochloric acid to form radium chloride. The properties of Radium, and the compounds it forms, have been put to good use from the time it was discovered to the present day.

Radium's unique "glowing" has been used to create self-luminous paints. The glowing paint can be found in old watches, instrument dials in older model aircrafts, and things alike. Radium also produces radon gas which is used in some cancer treatments(1 gram of radium can manufacture 0.0001 milliliters of radon a day.

Today, radium is considered to be dangerous in high amounts. It can cause many harmful health problems if inhaled or ingested accidentally; cancer leading to death is among the worse. The production of self-luminous paint was outlawed; the items the paint was used on was either destroyed, or kept in a secure location. It is said that the lab notebooks, belonging to radium's discoverers, are highly contaminated, and cannot be safely handled today.

Radium has 33 isotopes, none of which are stable, and none that occur naturally

Ra-226 is the more well-known, formerly used in self-luminous paint, currently used in cancer treatments in the form of radon. Radium has a half-life of about 1,600 years.