what is the element average atomic mass, the isotope atomic mass, and the number of neutrons?

Question

for element- actinium
- aluminum
- arsenic
-cobalt
-beryllium
-californium
thank you so much!!!!

Answer 1

You might want to bookmark this page:

http://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=&all=all&ascii=html&isotype=some

Subrtact the atomic number from the "isotope number" to get the number of neutrons.

Answer 2

1)The number of protons in a nucleus is called the atomic number and always equals the number of electrons in orbit about that nucleus (in a nonionized atom). Thus, all atoms that have the same number of protons--the atomic number--are atoms of the same element. 2)The atomic mass is the total mass of protons, neutrons and electrons in a single atom. 3)The total weight of an atom is called the atomic weight. It is approximately equal to the number of protons and neutrons, with a little extra added by the electrons for nucleus.