Search results
Results from the WOW.Com Content Network
There are two stable isotopes, 35 Cl (75.8%) and 37 Cl (24.2%), giving chlorine a standard atomic weight of 35.45. The longest-lived radioactive isotope is 36 Cl, which has a half-life of 301,000 years. All other isotopes have half-lives under 1 hour, many less than one second. The shortest-lived are proton-unbound 29 Cl and 30 Cl, with half ...
Chlorine. orthorhombic (oS8) Chlorine is a chemical element; it has symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element ...
Chlorine-37 (37 Cl), is one of the stable isotopes of chlorine, the other being chlorine-35 (35 Cl). Its nucleus contains 17 protons and 20 neutrons for a total of 37 nucleons. Chlorine-37 accounts for 24.23% of natural chlorine, chlorine-35 accounting for 75.77%, giving chlorine atoms in bulk an apparent atomic weight of 35.45(1) g/mol. [1]
Before the discovery of isotopes, empirically determined noninteger values of atomic mass confounded scientists. For example, a sample of chlorine contains 75.8% chlorine-35 and 24.2% chlorine-37, giving an average atomic mass of 35.5 atomic mass units.
For 12 C, the isotopic mass is exactly 12, since the atomic mass unit is defined as 1/12 of the mass of 12 C. For other isotopes, the isotopic mass is usually within 0.1 u of the mass number. For example, 35 Cl (17 protons and 18 neutrons) has a mass number of 35 and an isotopic mass of 34.96885. [7]
The atomic mass (m a or m) is the mass of an atom.Although the SI unit of mass is the kilogram (symbol: kg), atomic mass is often expressed in the non-SI unit dalton (symbol: Da) – equivalently, unified atomic mass unit (u). 1 Da is defined as 1 ⁄ 12 of the mass of a free carbon-12 atom at rest in its ground state. [1]
Chlorine has two stable and naturally occurring isotopes, chlorine-35 and chlorine-37. However, there are trace amounts in nature of the isotope chlorine-36, which occurs via spallation of argon-36. A total of 24 isotopes of chlorine have been discovered, with atomic masses ranging from 28 to 51. [7]
The standard atomic weight of a chemical element (symbol Ar° (E) for element "E") is the weighted arithmetic mean of the relative isotopic masses of all isotopes of that element weighted by each isotope's abundance on Earth. For example, isotope 63 Cu (Ar = 62.929) constitutes 69% of the copper on Earth, the rest being 65 Cu (Ar = 64.927), so.