Answer:
B. By atomic number.
Step-by-step explanation:
The atom is the most basic unit of matter with properties of a chemical element. The atom is the fundamental component of all matter. All atoms are made up of a central nucleus in which there are positively charged particles, the protons, around which other negatively charged particles, the electrons, move. The nucleus of the atom also has neutrons, which have a neutral charge.
The atomic number, which is represented by the letter Z, indicates the number of protons that are present in the nucleus of an atom. Determine the identity of an atom and its properties.
The atomic number is used to classify the elements within the periodic table of the elements.