ow do you find out the number of neutrons, protons and electrons? I have the mass & atomic number?

Question

I forget...

*How (sry spelling)

Answer 1

The number of protons is the atomic number. The number of neutrons is close to the number of protons but varies with the element and the isotope of the element. The number of electrons is the same as protons in a non ionized element and a few more or less if ionized, or missing altogether if you've messed the element up enough to make a plasma.

Answer 2

The atomic number = number of protons in an atom.

Carbon has an atomic number of six, so there are six protons in the atom.

The number of electrons = the number of protons. So carbon with an atomic number of 6 has 6 protons and 6 electrons.

The atomic mass = total mass of the protons and neutrons and electrons. Electrons don't weigh very much, so almost all the atomic mass consists of protons and neutrons.

Protons and neutrons weigh the same. So carbon with an atomic number of 6 and atomic mass of 12 must have 6 neutrons: 12 - 6 = 6.

So take the atomic mass, subtract, the atomic number, and you end up with the number of neutrons.


In real life, things are not entirely this neat and tidy. Elements have "isotopes", where the atomic number is the same, but the number of neutrons vary.

For example, most carbon has an atomic mass of 12, but some has an atomic mass of 13 (six protons and seven neutrons), and some has an atomic mass of 14 (6 protons and 8 neutrons).

The atomic mass found on the periodic table for a particular element, is an average of the isotopes found in nature according to their abundance, so atomic masses are not round numbers.

Answer 3

# protons =atomic number
# neutrons = atomic mass- atomic number or
atomic mass-number of protons

In most cases, number of electrons also equals the atomic number.