Question

can An object that is negatively charged could contain only electrons and no protons or neutrons

Answer 1

Let us imagine the object containing only the electrons. We know that two negative charges will repel each other and the force between two charges is proportional to $1/r^2$. Therefore, if the object contains only negative charges, it will be destroyed by the electric force due to Coulomb's law (if there is no very strong external force such as a force from strong magnetic field).

Therefore, if the object possesses negative charge it does not mean that the object consists of the negative charges only. For example, if we have a negatively charged metal ball, the negative charge is only on the surface, but the internal region has positive and negative charges, namely protons and electrons and also neutrons