What is the atomic mass of an element
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What is the atomic mass of an element
need simple answer thanks.
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Answer:
What is the atomic mass?
Atomic number is the number of protons in the nucleus. Since this also determines the number of electrons a neutral atom has, the atomic number indicates the chemical element. In other words, all atoms with the same atomic number are the same chemical element.
The atomic mass is, generally speaking, the sum of neutrons and protons in the nucleus. Neutrons work via the weak nuclear force to hold the nucleus together against the electrostatic repulsion of the positively charged protons - the more protons a nucleus contains, the more neutrons are necessary to keep it stable. Different numbers of neutrons and the same number of protons is what we mean by isotopes of an element.
When the number of neutrons is right then the nucleus is “stable,” which mostly means that it won’t decay if you leave it alone, or at least it won’t decay very quickly. There are some elements where all isotopes are so unstable (no amount of neutrons is close enough to right) that no naturally occurring atoms exist because they decay too quickly. Technetium (atomic weight 43, atomic mass 98, half life 400ky) is the lightest element like that.
The relationship between atomic mass and actual mass is, basically, where if you have Avogadro’s number (6.022E23) of atoms of a particular mass, then you also have that much in grams of that element. (There are a little over 28 grams in an ounce.) So, for example, if you have a balloon filled with 6.022E23 molecules of hydrogen (two hydrogen atoms per molecule, each atomic mass 1, with just a proton, and no neutrons), then the contents of the balloon has a mass of two grams. Two grams of hydrogen gas at room temperature and pressure is 22.4 liters, or about six gallons of hydrogen gas. (It’s a tiny bit more complicated due to things like E=mc^2 and how electrons weigh about a thousandth of a proton, but it’s close enough for a Quora article.)
6.022E23 is a lot of atoms (or molecules). If you made an end-to-end chain of those hydrogen molecules (about 3 angstrom in length) you’d have enough to get to the Sun and back 600 times. But it still fits into a reasonably sized party balloon, and weighs just 2 grams, or less than four thousandths of a pound.
Explanation:
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