Atoms do have physical form, despite their small size. While atoms are not visible to the naked eye, they are the building blocks of matter and have mass.
Atoms consist of a nucleus at the center, which contains protons and neutrons. Protons have a positive charge, while neutrons have no charge. Around the nucleus, there are electrons that have a negative charge and orbit the nucleus in specific energy levels or shells.
The mass of an atom is primarily concentrated in its nucleus, where the protons and neutrons are located. The mass of a proton and neutron is approximately 1 atomic mass unit (a.m.u). Electrons have a much smaller mass compared to protons and neutrons.
The total mass of an atom is determined by the sum of the masses of its protons, neutrons, and electrons. However, the mass of electrons is negligible compared to the mass of protons and neutrons, so the overall mass of an atom is primarily determined by the mass of its nucleus.
Therefore, even though atoms are incredibly small and not visible to the naked eye, they do possess mass due to the presence of protons and neutrons in their nucleus.