barium

> || Ba-130 || Stable || > || Ba-131 || 11.7 days || > || Ba-132 || Stable || > || Ba-133 || 10.5 years || > || Ba-133m || 1.6 days || > || Ba-134 || Stable || > || Ba-135 || Stable || > || Ba-135m || 1.2 days || > || Ba-136 || Stable || > || Ba-137 || Stable || > || Ba-137m || 2.6 minutes || > || Ba-138 || Stable || > || Ba-139 || 1.4 hours || > || Ba-140 || 12.8 days || > || Ba-141 || 18.3 minutes || > || Ba-142 || 10.7 minutes ||
 * **Element name:** Barium
 * **Element symbol:** Ba
 * **Atomic Number:** 56
 * **Color:** Silver
 * **Protons/Electrons:** 56
 * **Neutrons:** 81
 * **Most commom mass number:** 137.33
 * **Physical state at room temerature:** solid at 298 K
 * **Meaning of Element name:** Comes from the greek word //"barys"// meaning heavy.
 * **Uses of the element:** the sulphate version is used in paint, X-ray diagnostic work, glassmaking, making rubber, and can be found in rat poison.
 * **Biological improtance of element:** Barium has no biological role.
 * **Who discovered the** **element:** Barium was discovered by Sir Humphrey Davey at 1808 in England.
 * **How was the element discovered:** Baryta(barium oxide, BaO) was distinguished from lime(calcium oxide, CaO) by Scheele in 1774. Elemental barium was isolated by Sir Humphrey Davey in 1808 who electrolysed molten baryta.
 * **Physical properties of element:** meliting point: 1000K, boiling point: 2143K, density of solid: 3510kg, Mineral hardness: 1.25 (no units)
 * **Chemical properties of element:** Barium oxidizes in air, reacts vigoroulsy with water to form the hydroxide, liberating hydrogen. Barium reacts with almost all the non-metals, forming often poisouning compounds.
 * **Common compounds of element:** Barium dihydrate BaH2, Barium difluoride BaF2, Barium dichloride BaCl2, Barium oxide BaO
 * **Common Ions of element:**
 * **Isotopes of element:**
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 * **Isotope** || **Half Life** ||
 * **Barium is a metallic element, soft, and when pure is silvery white; It belongs to the alkaline earth group chemicly resembling calcium**


 * Resources:**
 * 1) http://periodic.lanl.gov/elements/56.html
 * 2) http://www.chemicalelements.com/elements/ba.html
 * 3) http://www.webelements.com/barium/