A small, dense region composed of protons and neutrons at the center of an atom.

Which of the following is responsible for the mass of an atom?

A subatomic particle with a negative charge.

The number of _______ in one atom of an element determines the atom's identity.

The atomic _____ tells you how many protons are there in an atom.

The arrangement of electrons in energy levels around an atomic nucleus.

A negatively charged particle, located in the outermost shell of an atom.

An element which has the same number of protons and electrons having no net charge.

This universal law states that like charges repel and unlike charges attract.