If only an element’s atomic number and weight are provided, what other atomic information can be determined for a neutral atom?

Question

1. only the number of protons and electrons
2. the number of protons, electrons and neutrons
3. only the valence electrons
4. only the number of protons and neutrons

Answer 1

The correct answer is 2. The atomic number tells us the number of protons in the nucleus of an atom, and the atomic weight is approximately equal to the sum of the protons and neutrons in the nucleus. Therefore, by knowing the atomic number and weight, we can determine the number of protons, electrons, and neutrons in a neutral atom.