What is the number of neutrons in the most common isotope of selenium?

Question

How many neutrons are in the most common isotope in the element selenium? (easier to understand)
- Mandi , GA

Answer 1

The most common isotope of selenium is Se-80, which would have 46 neutrons.

There are actually 5 stable isomers of selenium, and a sixth with a very long half-life. The atomic mass of selenium in the Periodic Table is 78.96 amu, but Se-79, the closest isotope to that weight, is actually unstable.

Answer 2

Selenium has at least 29 isotopes, of which 5 are stable, and 6 are nuclear isomers.

(80Se 49.61% Se is stable with 46 neutrons .
76Se 9.36% Se is stable with 42 neutrons
77Se 7.63% Se is stable with 43 neutrons
78Se 23.78% Se is stable with 44 neutrons
74Se 0.87% Se is stable with 40 neutrons )

Answer 3

45.
Se has atomic number 34 and mass number 79.
Thus the number of neutrons=79-34=45.
So there are 45 neutrons in Se.

Answer 4

http://en.wikipedia.org/wiki/Selenium#Isotopes