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The History of Calcium The Romans used lime, a compound of

calcium, by the first century A.D. (For more

on lime and its uses, see .)They called it calx, the Latin word for lime.

Calcium was first isolated and identified asan element in 1808 by Sir Humphry Davy.

The origin of calciums name is from theLatin words calx and calcis.

Properties of Calcium Back to Table of Contents

Uses of Calcium

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Properties of Calcium Calcium is very reactive. It cant be found pure in

nature.

Calcium reacts with water to form calcium

hydroxide (Ca(OH)2). It reacts with oxygen toform calcium oxide (CaO).CaO also reacts withwater to form calcium hydroxide.

Pure calcium is an alkaline earth metal. It is

silvery-white and fairly hard.

Calcium is the twentieth element. The mostcommon calcium isotope, Ca-40, has 20 protons,20 neutrons, and 20 electrons. NextBack

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Properties of Calcium (II)Calcium Isotope Half-life

Ca-40 Stable (non-radioactive)

Ca-41 103,000 years

Ca-42 StableCa-43 Stable

Ca-44 Stable

Ca-45 162.7 days

Ca-46 Stable

Ca-47 4.5 days

Ca-48 Stable

Ca-49 8.7 minutesNext

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Properties of Calcium (III) Calcium is a solid at 25 degrees Celsius (room

temperature).

Calcium is metallic and burns with a yellow-redflame.

Calcium has an average atomic mass of 40.078 amu

(atomic mass units.)

Calcium melts at 839C (1112.5K, 1542.2 F.)

Yet More Back

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Uses of Calcium Pure calcium has limited commercial use.

Calcium carbonate (CaCO3, limestone) is anantacid (think Tums.)

Mortar is made by mixing slaked lime (calciumhydroxide) with sand and water.

Most concretes today are based on Portlandcement. The cement is made from limestone, sand,

clay and gypsum. Gypsum is otherwise known as calcium sulfate

dihydrate (CaSO2H2O). It is very important forbuilding. Next

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More Uses of Calcium Calcium is an important nutrient for a wide range

of human organisms, including humans. Manymarine animals have shells of calcium.

Marble is a metamorphosed form of limestone andis composed of calcium carbonate.

Lime (calcium oxide), made from heating

limestone, is an extremely important industrialchemical.

Calcium chloride (CaCl2), can absorb water easily,even from the air. NextBack

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Obtaining Calcium(For Real This Time) To make pure calcium, you can heat calcium oxide with

aluminum

OR you can make it by the electrolysis of moltencalcium chloride.

You can obtain calcium from gypsum, limestone, andmarble. Limestone and marble are found in the earths

crust, and you can see conical pillars of limestonefilling caves all over the world.

Gypsum is formed by the evaporation of seawater. It isusually found lying in thick beds (of gypsum, of

course.) Atom Drawing of Calcium Table of Contents

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The Atom Diagram

20 p

20 n

Bibliography Table of ContentsBack