For example, sodium has 11 electrons. My homework question asks for number of protons (11), atomic number (11), number of neutrons (?), and mass number (?). How do I answer these?
2007-10-16 10:37:31 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
Well...you can't. Unless you look and take the most common isotope of sodium (use the periodic table)
2007-10-16 10:41:00 · answer #1 · answered by Anonymous · 0⤊ 0⤋
You have to look at the atomic mass on a periodic table to figure out the neurtrons. Like sodium's atomic mass rounded up is 23, so you do 23-11=12. So it has 12 neutrons. The mass number, I guess would mean the atomic mass but that's on the periodic table.Hope this helped
2007-10-16 10:42:29 · answer #2 · answered by Mo 2 · 0⤊ 0⤋
You have to assume that the teacher is asking about the stable isotope(s) of that element. Go to a periodic table of elements and the mass number will be listed.
Sodium has one stable isotope with as mass number of 23. Subtract 11 from 23 to get the number of neutrons.
.
2007-10-16 10:42:07 · answer #3 · answered by tlbs101 7 · 0⤊ 0⤋
I don't know how else you would find it but to look it up on the periodic table. and the answer is 12 neutrons and 23 is mass number
2007-10-16 10:41:13 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Your periodic table doesn't give you a mass number or atomic weight? The number of electrons is the number of protons minus the charge of the ion. The mass number
2016-05-22 23:51:52 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Well, your mass number is pretty much the atomic mass rounded to the nearest whole number.
so once you round your atomic mass, just subtract the number of protons, and there's your number of neutrons.
2007-10-16 10:45:22 · answer #6 · answered by menacing_platypus 3 · 0⤊ 0⤋