No, a nucleus does not contain electrons. Electrons are negatively charged subatomic particles that orbit the nucleus in specific energy levels or electron shells. The nucleus, on the other hand, is the central region of an atom that contains protons and neutrons tightly bound together. Protons are positively charged particles, and neutrons have no charge. The number of protons determines the atomic number of an element and defines its identity, while the number of neutrons can vary to form...

1. Isotopes: Isotopes are variants of an element that have the same number of protons (same atomic number) but different numbers of neutrons (different mass numbers). This means isotopes of an element have the same chemical properties but vary in atomic mass. For example, carbon-12 (12C) and carbon-14 (14C) are isotopes of carbon.

2. Isotones: Isotones are nuclei of different elements that have the same number of neutrons but different numbers of protons. In other words, isotones share the...

1. Mass Defect: The mass defect refers to the difference between the mass of an atomic nucleus and the sum of the masses of its individual protons and neutrons. It arises from the conversion of mass to energy during the formation of the nucleus. The mass defect is responsible for the release of energy in nuclear reactions, as described by Einstein's famous equation E=mc².

2. Packing Fraction: The packing fraction is a measure of how tightly nucleons (protons and neutrons) are packed within an...