Definition of beta. 1  1 : the 2nd letter of the Greek alphabet â see alphabet table. 2  2 : beta particle. 3  3 : a measure of the risk potential of a stock or an investment portfolio expressed as a ratio of the stock's or portfolio's volatility to the volatility of the market as a whole.
Chlorine has been used as a chemical warfare agent. Sources: In nature, chlorine is only found in the combined state, most commonly with sodium as NaCl and in carnallite (KMgCl 3 â¢6H 2 O) and sylvite (KCl). The element is obtained from chlorides by electrolysis or via the action of oxidizing agents. Element Classification: Halogen. Density (g/cc): 1.56 (@ -33.6 Â°C).
Chlorine is a chemical element with symbol Cl and atomic number 17. It also has a relative atomic mass of 35.5. Chlorine is in the halogen group (17) and is the second lightest halogen following fluorine.The element is a yellow-green gas under standard conditions, where it forms diatomic molecules.Chlorine has the highest electron affinity and the third highest electronegativity of all the reactive elements.he most common compound of chlorine, sodium chloride, has been known since ancient times; archaeologists have found evidence that rock salt was used as early as 3000 BC and brine as early as 6000 BC. Around 1630, chlorine was recognized as a gas by the Flemish chemist and physician Jan Baptist van Helmont.