Question

Why is the atomic number represented by Z?

Answer 1

Hint: The number of protons in the nucleus of every atom of a chemical element is known as the atomic number or proton number (symbol Z). A chemical element's atomic number is the only way to identify it. It is the same as the nucleus' charge number. The atomic number is also equivalent to the number of electrons in an uncharged atom.

Complete answer:
With James Chadwick's discovery of the neutron in 1932, all study of nuclear electrons came to an end. An atom of gold now has 118 neutrons rather than 118 nuclear electrons, and its positive charge is completely derived from 79 protons. As a result, after 1932, the atomic number Z of an element was discovered to be the same as the proton number of its nuclei.
Before the contemporary synthesis of concepts from chemistry and physics, the traditional sign Z simply denoted an element's numeric position in the periodic table, whose order is approximately, but not fully, compatible with the order of the elements by atomic weights. The term Atomzahl (and its English counterpart atomic number) became widely used in this sense only after 1915, when it was suggested and shown that this Z number was both the nuclear charge and a physical property of atoms.
The letter Z is thought to be derived from the German term atomzahl (atomic number). Prior to 1915, each element's assigned number in the periodic table was referred to as Zahl (just number).

Note:
Because of the amount of electrons present in the neutral atom, which is Z, each element has a unique set of chemical characteristics (the atomic number). The quantum mechanics laws dictate the arrangement of these electrons. The amount of electrons in each element's electron shells, especially the outermost valence shell, determines its chemical bonding behaviour. As a result, the chemical characteristics of an element are determined only by its atomic number; as a result, an element may be described as any mixture of atoms with a particular atomic number.