mass number

mass number : The mass number ( A), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. Because protons and neutrons both are baryons, the mass number A is identical with the baryon number B as of the nucleus as of the whole atom or ion. The mass number is different for each different isotope of a chemical element. This is not the same as the atomic number ( Z) which denotes the number of protons in a nucleus, and thus uniquely identifies an element. Hence, the difference between the mass number and the atomic number gives the number of neutrons ( N) in a given nucleus: N=A−Z. The mass number is written either after the element name or as a superscript to the left of an element's symbol. For example, the most common isotope of carbon is carbon-12, or 12 C, which has 6 protons and 6 neutrons. The full isotope symbol would also have the atomic number ( Z) as a subscript to the left....   More from Wikipedia

mass number : The mass recorded by a mass spectrometer can refer to different physical quantities depending on the characteristics of the instrument and the manner in which the mass spectrum is displayed. The accurate mass (more appropriately, the measured accurate mass) is an experimentally determined mass..   More from Wikipedia

  series, arranged in suggested viewing order, go to my website. For a playlist containing all the videos in this series, click here: www.youtube.com (1) Proton, neutrons, and electrons mass and charge. Atomic mass units and elementary charge units (2) Mass number (A), atomic number (charge number, Z) (3) Conventional symbolism for nucleii. Alpha, beta, and gamma particles (4) Alpha, beta, and gamma decay (5) Problems (6) Mathematics of radioactive decay; decay constant (lambda) (7) A problem ( ...

  Physics: Nuclear physics. Protons, neutrons, and electrons. Mass number (A) and atomic number (charge number, Z); conventional symbolism for nuclei. Alpha, beta, and gamma particles; how decay particles behave in magnetic fields. Mathematics of radioactive decay; decay constant; half-life. Biological effects of radiation; rads, RBE (relative biological effect), rems. This is a recording of a tutoring session, posted with the student's permission. These videos are offered on a "pay-what-you-like ...

Question : If you just read the definition from the book "Mass number" is equal to the sum of protons and neutrons in an atom's nucleus while "Atomic Mass" is equal to the mass number. Doesn't that mean that we're using two words to describe the same thing? What's the point of that?

Answer : Atomic mass is the average of the masses of the existing isotopes in an element, but the mass number is the sum of the protons and neutrons in the nucleus of an atom...   More from Yahoo Answers

Question : i'm supposed to be able to find the number of electrons and neutrons in a molecule, but i'm a little confused here. what's the difference between the mass number and the atomic number? make it simple please. i'm confused easily, lols.

Answer : Atomic number equals the number of protons (positively charged) in a nucleus, while the mass number (AKA "atomic weight" or "atomic mass") is the number of protons plus neutrons. In a neutrally charged atom, protons and electrons (negatively charged) will number the same. They've started using "mass number" to differentiate it from the average "atomic mass" gotten by averaging all the isotopic weights for an element...   More from Yahoo Answers