Atomic numbers and mass numbers are represented in an atom as follows:
Atomic Number (Z): The atomic number represents the number of protons in the nucleus of an atom. It is a fundamental characteristic of an element and determines its unique identity. The atomic number is denoted by the symbol "Z" and is typically written as a subscript to the left of the element's symbol. For example, the atomic number of carbon (C) is 6, so it is written as "C" with a subscript "6".
Mass Number (A): The mass number represents the total number of protons and neutrons in the nucleus of an atom. It gives an indication of the mass of an atom and is denoted by the symbol "A". The mass number is typically written as a superscript to the left of the element's symbol. For example, carbon-12 (C-12) has a mass number of 12, so it is written as "C" with a superscript "12".
To represent a specific atom, you would combine the atomic number and mass number notation. For example, carbon-12 (C-12) would be represented as:
C | 12
This indicates that the atom is carbon (C) with an atomic number of 6 and a mass number of 12, indicating it has 6 protons and 6 neutrons in its nucleus.