Atomic Theory definitions Flashcards
Atomic Theory definitions
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Atomic Theory A scientific theory that matter is composed of discrete units called atoms. Atom The smallest unit of matter that retains the identity of a chemical element. Isotope Atoms of the same element with the same atomic number but different mass numbers. Subatomic Particles Particles that are smaller than an atom, including protons, neutrons, and electrons. Conservation of Mass A principle stating that mass cannot be created or destroyed in a chemical reaction. Element A substance consisting of atoms which all have the same number of protons. Compound A substance formed when two or more chemical elements are chemically bonded together. Mass Number The total number of protons and neutrons in an atomic nucleus. Chemical Reaction A process that involves rearrangement of the molecular or ionic structure of a substance. Proton A subatomic particle found in the nucleus of every atom, carrying a positive charge. Neutron A subatomic particle found in the nucleus of atoms, having no electric charge. Electron A subatomic particle with a negative charge, found in all atoms and acting as the primary carrier of electricity. Molecular Structure The arrangement of atoms within a molecule. Carbon A chemical element with symbol C and atomic number 6, known for its various allotropes. Dalton's Postulates A set of principles proposed by John Dalton to describe the nature of atoms and matter.