What does the atomic number of an element indicate?

The atomic number of an element is defined as the total number of protons in the nucleus of an atom. Since atoms are electrically neutral, the number of protons in an atom is equal to the number of electrons surrounding the nucleus. Therefore, option B is correct as it encompasses both the protons and electrons associated with that element, reflecting its foundational role in defining the element's identity and its place on the periodic table.

The atomic number is crucial for distinguishing between different elements. Each element has a unique atomic number, which remains constant regardless of the number of isotopes or variations in neutrons. Understanding the atomic number helps in various fields, including chemistry, physics, and even in funeral service education when discussing the implications of elemental composition in embalming fluids or the decomposition of organic matter.

In contrast, other options reference aspects that do not define the atomic number. The total number of neutrons relates to isotopes rather than the atomic number itself. The total mass of the element involves both protons and neutrons, making it a different concept. Additionally, the total number of isotopes refers to variations of an element and does not pertain to the atomic number.