this is a physical science question
2006-06-09 06:53:37 · 4 answers · asked by Anonymous in Education & Reference ➔ Homework Help
Look on a periodic table.
It should be listed below the atomic number as a decimal value. The mass number is an average mass (in atomic mass units) of an element, based on different isotopes. It equals the number of protons + the number of neutrons in the nucleus.
2006-06-09 06:56:30 · answer #1 · answered by Steven B 6 · 0⤊ 0⤋
The easiest way is to use the Periodic Table.
It shows that sodium (Na) has the atomic mass of 23 approximately.
2006-06-09 17:57:59 · answer #2 · answered by Giovanna 1 · 0⤊ 0⤋
M not xactly sure but guess...
see, in an atom the number of protons is generally equal to that of electrons.
But it's not always true.. sometimes protons exceed the number
As in here, the at. mass of Na is 23
So i guess it has 11 electrons and 12 protons.
that makes it 23 on the whole.
Or may be there's some other xplanation
2006-06-09 14:04:51 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Look it up in the Periodic Table. It's roughly 23.
2006-06-09 13:56:45 · answer #4 · answered by TheOnlyBeldin 7 · 0⤊ 0⤋