Atomic Structure and Radioactivity Atoms and Subatomic Particles An atom is the basic unit of an element, consisting of three fundamental subatomic particles: P...
An atom is the basic unit of an element, consisting of three fundamental subatomic particles:
The atomic number represents the number of protons, while the mass number is the total number of protons and neutrons.
Atoms of the same element with different numbers of neutrons are called isotopes. Isotopes have the same atomic number but different mass numbers. When an atom gains or loses electrons, it becomes a charged ion.
Carbon-12 has 6 protons and 6 neutrons: Atomic number = 6, Mass number = 6 + 6 = 12
Carbon-14 has 6 protons and 8 neutrons: Atomic number = 6, Mass number = 6 + 8 = 14
Carbon-12 and Carbon-14 are isotopes of carbon.
Certain isotopes are radioactive, meaning their nuclei are unstable and emit particles or energy:
The half-life is the time it takes for half of the radioactive atoms in a sample to decay.
Low levels of radiation exist naturally, known as background radiation. While radiation can be hazardous, it has many beneficial applications in medicine (e.g., diagnosis and treatment), industry (e.g., gauging and monitoring), and scientific research.
Nuclear fission is the splitting of heavy nuclei, releasing energy. Nuclear fusion is the joining of light nuclei, also releasing energy. These processes are the basis of nuclear power and weapons.
Our understanding of atomic structure has evolved through various models, including: