Learn what atomic number is , how to calculate it and why it is important for the periodic table. Find out the difference between atomic number and mass number , and see examples of isotopes and orbital energy levels. Atomic Number Definition The atomic number or proton number of an element is defined as the number of protons present in the nucleus of each atom of that element. The number of protons is the characteristic feature that imparts uniqueness to each element compared to all other elements. Elements are different because of their atomic number . Atomic Number (Z) Atomic Number of element is defined as the Number of the protons in nucleus. It is denoted by the Letter Z Z = Number of protons present in nucleus For example, The number of protons in hydrogen atom is 1,So Atomic Number of Hydrogen is 1 Similary the number of protons in Sodium atom is 11, So Atomic Number of Sodium is 11 Atomic Number of element depends only on the number of protons in the elements. it does not depends on number of electrons or neutron. We may use this ... Learn what atomic number is , how to find it, and why it is important for identifying elements. See the list of atomic numbers and symbols of all 118 elements in the periodic table.
