What two forces act in the nucleus to create a 'nuclear tug-of-war'? a.
Covalent bond, ionic bond
c.
Van der waals force, dipole
b.
Electrostatic repulsion, strong nuclear force
d.
All of the above

Electrostatic repulsion, strong nuclear force

Explanation:

The nucleus consists of protons and neutrons. protons are positively charged while neutrons possess no charge.

Since protons are positively charged, they repel each other strongly (like charges repel). This strong repulsion of like charges makes the nucleus somewhat unstable leading to spontaneous fission of heavy nuclei.

However, an opposing force called nuclear attractive force tends to hold the nucleons together. This attraction occurs when two nucleons are bonded by a particle called a π meson.

Hence, the two forces that act in the nucleus to create a  'nuclear tug-of-war' are electrostatic repulsion and a strong nuclear force.

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements