Which of the following nuclei would be most stable?

a nucleus that contains 10 protons and 10 neutrons
a nucleus that contains 7 protons and 7 neutrons
a nucleus that contains 100 protons and 200 neutrons
a nucleus that contains 84 protons and 84 neutrons

A nucleus that contains 10 protons and 10 neutrons

Explanation:

as we know that nuclear stability depends on various factors out of which first part on which stability depends on is N/P ratio

if N/P ratio lie between 1 and 1.2 then nuclei is a stable nuclei and if the ratio of N/P is greater than 1.2 then it is unstable.

As the number of protons increases then the number of neutrons must be more than number of neutrons so that mutual repulsion force of protons are counter balanced.

Next parameter is even combinations of neutrons and protons are always more stable than odd combinations of neutrons and protons

So correct answer will be

A nucleus that contains 10 protons and 10 neutrons