Chlorine Atomic Mass
Chlorine (17 Cl) has 25 isotopes with mass numbers ranging from 28 Cl to 52 Cl and 2 isomers (34m Cl and 38m Cl). There are two stable isotopes, 35 Cl (75.77%) and 37 Cl (24.23%), 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.
2.4 Atomic Weights
Atoms are small pieces of matter, so they have mass. As noted in Section 2.1, a key postulate of Dalton's atomic theory is that mass is conserved during chemical reactions. Much of what we know about chemical reactions and the behavior of substances, therefore, has been derived by accurate measurements of the masses of atoms and molecules (and macroscopic collections of atoms and molecules) that are undergoing change. Chances are that you are already using mass measurements in the laboratory portion of your course in order to monitor changes that occur in chemical reactions. In this section we will discuss the mass scale that is used for atoms and introduce the concept of atomic weights. In Section 3.3 we will extend these concepts to show how these atomic masses are used to determine the masses of compounds and molecular weights.
The molecular formula for Chlorine is Cl. The SI base unit for amount of substance is the mole. 1 grams Chlorine is equal to 0.13029 mole. Note that rounding errors may occur, so always check the results. Element Chlorine (Cl), Group 17, Atomic Number 17, p-block, Mass 35.45. Sources, facts, uses, scarcity (SRI), podcasts, alchemical symbols, videos and images. Chlorine has 17 protons in its nucleus and its most common isotope has 18 neutrons. That means that the total mass of a chlorine atom is about 35.5 atomic mass units. Chlorine has 17 protons in its nucleus and its most common isotope has 18 neutrons. Is chlorine 37 radioactive?
The Atomic Mass Scale
Although scientists of the nineteenth century knew nothing about subatomic particles, they were aware that atoms of different elements have different masses. They found, for example, that each 100.0 g of water contains 11.1 g of hydrogen and 88.9 g of oxygen. Thus, water contains times as much oxygen, by mass, as hydrogen. Once scientists understood that water contains two hydrogen atoms for each oxygen, they concluded that an oxygen atom must have times as much mass as a hydrogen atom. Hydrogen, the lightest atom, was arbitrarily assigned a relative mass of 1 (no units), and atomic masses of other elements were at first determined relative to this value. Thus, oxygen was assigned an atomic mass of 16.
Chlorine Atomic Mass Average
Today we can determine the masses of individual atoms with a high degree of accuracy. For example, we know that the atom has a mass of g and the atom has a mass of g. As we noted in Section 2.3, it is convenient to use the atomic mass unit (amu) when dealing with these extremely small masses:
Chlorine Atomic Mass
The amu is presently defined by assigning a mass of exactly 12 amu to an atom of the isotope of carbon. In these units the mass of the nuclide is 1.0078 amu and that of the nuclide is 15.9949 amu.