The answer is d Thus, the first energy level holds 2 * 1^2 = 2 electrons, while the second holds 2 * 2^2 = 8 electrons. Each orbital. The third energy level can hold up to 18 electrons, meaning that it is not full when it has only electrons.
Instability of an atoms nucleus can result from an excess of either neutrons or protons . So neutrons and protons .
Answer:
protons and neutrons
Explanation:
protons and neutrons is equal to mass number