Here's why:
* Mass Comparison: Protons and neutrons have a mass of approximately 1 atomic mass unit (amu), while electrons have a mass of only about 1/1836 amu. This means electrons are significantly lighter than protons and neutrons.
* Atomic Mass: The atomic mass of an element is primarily determined by the number of protons and neutrons in its nucleus (which are collectively called nucleons). Since electrons are so light, their contribution to the overall atomic mass is negligible.
Therefore, even though electrons play a crucial role in chemical bonding and determining the atom's overall charge, their contribution to the atom's weight is almost insignificant.
