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Atomic Mass
Atomic mass is the mass of protons, neutrons, and electrons in a single specific atom.
1,752 Questions
Number of protons plus the number of neutrons (electrons don't matter as they have such a small mass).
How do you calculate effective atomic mass?
Aeff=(Zeff)/((Z/A)eff)
Zeff=wi*Zi
wi is weight fraction in ith element in compound. for example water has 0.112 H and 0.888 O.
(Z/A)eff=wi*Zi/Ai
What is the mass (in grams) of 9.18 1024 molecules of methanol (CH3OH)?
9.18x10^24 molecules CH3OH x 1 mole/6.02x10^23 molecules x 32 g/mole = 488 g (to 3 sig figs)
Atomic mass used in a sentence?
The atomic mass of an element is the weighted average of the masses of all the stable isotopes of the element (if it has any), weighted by the natural occurrence levels of the isotopes in the elements as found on earth or in the atmosphere.
What is the atomic mass rounded of boron?
Boron - B - Group III
The atomic number is 5.
The mass number is 11.
What can the atomic mass tell you about an atom?
the mass of an atom of a chemical element expressed in atomic mass units. It is approximately equivalent to the number of protons and neutrons in the atom (the mass number) or to the average number allowing for the relative abundances of different isotopes.
Atomic mass equals the number of what?
The atomic mass NUMBER equals the number of protons and neutrons in an atom.
DO NOT confuse this with the mass of an atom.
What is the average atomic mass for chlorine?
Chlorine is a non meta element. Atomic mass of it is 35.
Why does the modern periodic table not arrange argon in order of increasing atomic mass?
The inversion is due to the isotopic composition of these elements.
The atomic number increases but the atomic mass stays the same?
The atomic number increases but the atomic mass stays the same after the emission of a beta particle by a radioactive atom.
Why don't elements in the periodic table have whole numbers for their atomic masses?
If we look at hydrogen, we see it's the simplest of all the elements. It's basically one proton with an electron hanging around. Problem is, if we look at a whole bunch of hydrogen atoms, we find one every once in a great while that has a neutron hanging on to the proton in the nucleus. That atom of hydrogen has about twice the mass of a "regular" hydrogen atom. It's a distinct isotope of hydrogen. There are even some atoms of hydrogen that have two neutrons hanging on to that proton in the nucleus. The atoms of hydrogen with the neutrons are rare, but the difference in their masses and the fraction of the naturally occurring element that they make up must be accounted for.
As we go on up the periodic table to heaver elements, we find that pretty much all the elements have several isotopes that occur in nature, and some have significant portions distributed over two or more isotopes. Take Boron. It's atomic number is 5. How many neutrons are in a boron atom? Well, roughly 80% have 6 neutrons while about 20% have 5. When we weigh a sample of boron in the lab, we need to account for that.
If we look at tin, we find it has 10 naturally occurring isotopes! And we have to account for them all when we have a sample of tin because they are each in there in some amount. That's why the atomic masses of the elements aren't whole numbers. It would be simple if they did, but science demands we account for the variables in nuclear structure.
What is the atomic mass of butane?
The atomic mass of butane (C4H10) is approximately 58.12 grams/mol.
Nickel's atomic number is 28.
It's atomic weight on the periodic table is 58.6934.
It's boiling point is 2913 oC.
It's melting point is 1455 oC.
Mass number varies with the individual isotopes.
