The nucleus of an isotope of chlorine contains 20 neutrons

true

Explanation:

i say this because an atom of chlorine-35 contains 18 neutrons (17 protons + 18 neutrons = 35 particles in the nucleus) while an atom of chlorine-37 contains 20 neutrons (17 protons + 20 neutrons = 37 particles in the nucleus). Adding or removing a neutron from an atom's nucleus creates isotopes of a particular element.

the dissolution of polymer can be thermodynamically described in 2 steps.

the cold front replaces the warmer air at the ground level changing the wind to be breezy and denser.there is also an immediate drop in the temperature.