Final answer:
The force of attraction between the protons and the shared pair of electrons is the electromagnetic force. The strong nuclear force holds the nucleus together.
Step-by-step explanation:
The force of attraction between the protons in the nucleus and the shared pair of electrons in the outer shell is called the electromagnetic force. This force acts between particles with opposite charges, such as protons and electrons. It is responsible for holding the electrons around the nucleus and creating chemical bonds.
However, it is important to note that within the nucleus, there is also another force called the strong nuclear force. This force acts between protons, neutrons, and between protons and neutrons, and it is much stronger than the electromagnetic force. The strong nuclear force is what holds the nucleus together, overcoming the electrostatic repulsion between the positively charged protons.