A. Protons and neutrons make up the nucleus of an atom. Write 3 - 4 sentences describing the electrostatic force between each pair of particles (proton-proton, proton-neutron, neutron-neutron) and the strong nuclear force between each pair of particles.

b. Write 3 - 4 sentences explaining why a nucleus tends to become less stable if the number of neutron is decreased.

c. Write 2 - 3 sentences describing Einstein's explanation for why the total starting mass is greater than the total ending mass after a nuclear reaction.

a) Electrostatic force between proton and proton will be repulsive. Electrostatic force between proton and neutron will be attractive. Electrostatic force between neutron and neutron will be zero. Strong nuclear force between proton and proton, neutron and proton and neutron and neutron will be attractive and their magnitude will be far greater. Electrostatic force is inversely proportional to the square of the distance between two particles and the nuclear force is inversely proportional to greater power of the distance between the particles. In other words nuclear force between any two nuclear particles changes at very fast rate when we change the distance between them.

b) If the number of neutron in nucleus is decreased, the average distance between any two protons is decreased. Due to it, the repulsive force between them is increased. Therefore nucleus becomes less stable.

Explanation:

c) After the nuclear reactions like fusion or fission, total mass of the product is less than the total mass of total reactant. It is due to conversion of some mass of reactant into energy. This energy is released as heat, light and sound energy. The product becomes more stable.

a) Proton-proton: high repulsive electrostatic, very high attractive nuclear force. Proton-neutron: no electrostatic forces since neutrons are not charge carriers, high attractive nuclear force. Neutron-neutron: no electrostatic force for the same reason and huge attractive nuclear force.

b) There are two types of forces in the nuclei: repulsive electrostatic and attractive nuclear. Nuclear act between all nucleons, electrostatic only between protons. To make a nucleus stronger, increase number of attractive forces by increasing amount of neutrons.

c) Cause due to equivalence between mass and energy E=mc^2 change in energy (which happens in nuclear reaction) causes on change in mass. Starting mass just converts to energy, that's why it's greater than the ending mass.