What purpose do neutrons serve in the nucleus ? What happens if there are too many or too few neutrons?

These nuclei with different numbers of neurons are called isotopes

neutrons' main function is to attract each other and keep the nucleus of an atom intact. a nucleus will become unstable if there are too many or too few neutrons in it.

Explanation:

too many= it will undergo beta decay (the neutrons will changes into proton)

too few= there will be an imbalance between forces which leads to nuclear imbalance

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).