2006-12-02 06:02:05 · 5 answers · asked by starreyes2000_2000 1 in Science & Mathematics ➔ Chemistry
The mass number (A), also called atomic mass number or nucleon number, is the number of nucleons (protons and neutrons) in an atomic nucleus.
2006-12-02 06:04:43 · answer #1 · answered by Bad Kitty! 7 · 1⤊ 0⤋
You've combined/confused two different numbers.
The MASS NUMBER of an atom refers to the protons + neutrons.
Atoms with the same number of protons but different numbers of neutrons are called isotopes. They are the same element but have different mass numbers.
The ATOMIC MASS refers to the average mass of all of the naturally occurring isotopes of an element with their % abundance taken into account (so its called a "weighted" average).
2006-12-02 14:07:48 · answer #2 · answered by The Old Professor 5 · 1⤊ 0⤋
DefinitIon ALL ISOTOPES HAVE THE SAME ATOMIC NUMBER Z
The only difference lies in the NUMBER OF NEUTRONS
Atomic number A = N+Z
where N number of neutrons ; Z number of protons
2006-12-02 14:06:16 · answer #3 · answered by maussy 7 · 0⤊ 0⤋
the weighted average of the number of neutrons plus the number of protons
2006-12-02 14:04:00 · answer #4 · answered by DrWalrus 2 · 0⤊ 0⤋
the # of neutrons +hte # of protons
2006-12-02 14:03:08 · answer #5 · answered by Anonymous · 0⤊ 1⤋