"A particle that consists of a nucleus of protons and neutrons surrounded by an electromagnetically-bound cloud of electrons."
The basic structure of atoms, including the subatomic particles that make them up and the rules that govern how they are arranged. This topic includes discussions of atomic models, electron configuration, and the periodic table of elements.
Matter: The physical substance that makes up everything in the universe.
Elements: The fundamental building blocks of matter, which are characterized by the number of protons in an atom's nucleus.
Atoms: The basic unit of matter, consisting of a nucleus of protons and neutrons, surrounded by electrons.
Electrons: Negatively charged particles that orbit the nucleus of an atom.
Protons: Positively charged particles that are part of the nucleus of an atom.
Neutrons: Particles that have no charge and are part of the nucleus of an atom.
Periodic Table: A chart of the elements arranged in order of their atomic number, which reflects the periodicity of their physical and chemical properties.
Atomic Structure: The way in which the components of an atom are arranged, including the nucleus and its particles, as well as the electron cloud.
Isotopes: Variants of an element that differ in the number of neutrons their atoms contain.
Radioactivity: The emission of radiation from certain types of matter, especially from nuclear reactions.
Atomic Mass: The collective mass of the protons, neutrons, and electrons in an atom.
Quantum Mechanics: The study of the behavior of matter and energy at the atomic and subatomic level, which involves the principles of wave-particle duality and uncertainty.
Electron Configuration: The arrangement of electrons in the energy levels and sublevels of an atom.
Valence Electrons: The electrons in the outermost energy level of an atom that are involved in chemical bonding.
Photon: A unit of energy associated with electromagnetic radiation, including light, which may be emitted or absorbed by atoms and molecules.
Electrons: They are negatively charged particles present in the atomic structure and play a significant role in chemical reactions.
Protons: The positively charged particles present in the atomic structure.
Neutrons: The electrically neutral particles present in an atomic nucleus.
Atomic Nucleus: The central part of an atom that contains protons and neutrons.
Isotopes: Different forms of the same element that have the same number of protons but different numbers of neutrons.
Energy Levels: The different energy states of an electron in an atom.
Orbitals: The region around an atomic nucleus where an electron is likely to be found.
Ionization Energy: The amount of energy required to remove an electron from an atom or molecule.
Excited States: When an atom absorbs energy, it moves to a higher energy level known as an excited state.
Atomic Spectra: The set of frequencies of electromagnetic radiation that are emitted or absorbed by an atom.
Quantum Mechanics: The branch of physics that studies the behavior of matter and energy at the atomic and subatomic scale.
Radioactivity: The spontaneous emission of particles or electromagnetic radiation from the nucleus of an unstable atom.
Fusion and Fission: Nuclear reactions that involve the combination of atomic nuclei or the splitting of atomic nuclei.
"The chemical elements are distinguished from each other by the number of protons that are in their atoms."
"The number of protons that are in their atoms."
"Any atom that contains 11 protons is sodium, and any atom that contains 29 protons is copper."
"The number of neutrons."
"Atoms are so small that accurately predicting their behavior using classical physics is not possible due to quantum effects."
"Typically around 100 picometers across."
"More than 99.94%."
"If the numbers of protons and electrons are equal, as they normally are, then the atom is electrically neutral."
"If it has more protons than electrons, it has a positive charge, and is called a positive ion (or cation)."
"If an atom has more electrons than protons, then it has an overall negative charge, and is called a negative ion (or anion)."
"The electrons of an atom are attracted to the protons in an atomic nucleus by the electromagnetic force." "The protons and neutrons in the nucleus are attracted to each other by the nuclear force."
"The nuclear force is usually stronger than the electromagnetic force."
"When the repelling electromagnetic force becomes stronger than the nuclear force."
"The nucleus splits and leaves behind different elements."
"Chemical bonds to form chemical compounds such as molecules or crystals."
"The ability of atoms to attach and detach from each other."
"Chemistry is the discipline that studies these changes."
"A nucleus of protons and neutrons."
"If any are present, have no electric charge."