Mass number<span> is the </span>number<span> of protons </span>and<span> neutrons in an atom.
</span>Atomic mass<span> is the average </span>mass<span> of all the isotopes of a certain type.</span>
Answer:
An atom is a particle of matter that uniquely defines achemical element. An atom consists of a central nucleus that is usually surrounded by one or more electrons. Each electron is negatively charged. The nucleus is positively charged, and contains one or more relatively heavy particles known as protons and neutrons.
If a metal is less reactive than carbon, it can be extracted from its oxide by heating with carbon. The carbon displaces the metal from the compound, and removes the oxygen from the oxide. This leaves the metal.
