What two things do you add together to get the atomic mass of an atom?

Answer 1

The atomic weight (not mass) of a chemical element is the ratio between the average mass of the atoms of this element to 1/12 from the Atomic Mass of carbon-12.

The atomic mass is a term applied only to specific isotopes; the unit is the same as above. Is a value denoting the total mass of all the protons, neutrons, and electrons in an isotope.

The mass number tells us the number (the sum) of protons and neutrons in the nucleus of an atom.

The atomic number, on the other hand, tells us how many protons are in the nucleus of an atom.

IUPAC publish periodically tables of atomic weights - the last edition is from 2009-2010.

For the atomic masses of isotopes the last published edition is The AME 2003 atomic mass evaluation, edited by Audi, Wapstra and Thibault.

Answer 2

The number of protons and the number of neutrons.

Answer 3

Add the number of protons and neutrons, to get atomic mass number.

Answer 4

Mass number is the sum of the number of protons and the number of neutrons in the atom:

Mass Number = Atomic Number + Number of Neutrons.

Answer 5

The atomic mass is the wieghted average of all naturally occurring isotopes of an element. As an example: (20%)Boron-10 & (80%)Boron-11= 10*0.2+11*0.8=10.81AMU(atomic mass number)

Answer 6

The mass number of an element is the number of protons (atomic number) plus the number of neutrons.

Answer 7

To determine mass number of an isotope, you add the number of protons and number of neutrons for that isotope.