Understanding Closed Neutron Shells: Determining the Elements with Stable Nuclei

[briteliner]

Homework Statement

which of the following has closed neutron shells? (the number in front should be a superscript) 36S, 50V, 50Ca, and there are more but i just want to understand why.

Homework Equations

The Attempt at a Solution

i know the answers, i just don't know how to get there. for example 36S has closed neutron shells, but how do i know this? please help

 

[malawi_glenn]

Find the number of neutrons in the nuclei and compare with the Nuclear Shell Model.

http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/shell.html