Final answer:
Small atoms with fewer than 30 protons often have equal numbers of protons and neutrons in nature, especially for lighter elements where a 1:1 ratio is common for nuclear stability. Heavier elements generally require more neutrons for stability due to increased electrostatic repulsion in larger nuclei.
Step-by-step explanation:
In nature, small atoms with less than 30 protons often do have equal numbers of protons and neutrons; especially those closer to hydrogen in the periodic table. This is because the mass of an atom is roughly equal to the sum of its protons and neutrons, as electrons have significantly less mass and do not affect the overall mass appreciably.
For lighter elements, the 1:1 ratio helps maintain nuclear stability. Hydrogen, the lightest element, typically has no neutrons but its isotope deuterium has one proton and one neutron. A high percentage of the lighter elements, up to calcium with atomic number 20, follow this 1:1 ratio closely. Heavier elements generally require more neutrons than protons to help offset the increasing electrostatic repulsion between the positively charged protons in the denser and larger nuclei.
Thus, finding neutral atoms— with equal numbers of protons and electrons — and a 1:1 ratio of protons to neutrons in nature is not uncommon for atoms with atomic numbers less than 30. However, the ratio starts deviating as the elements get heavier.