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Chemistry/atoms
Elements, atoms, chemical bonding, isotopes,
Term | Definition |
---|---|
Atoms | Smallest particles of matter; retains all of the characteristics of an element |
Atomic structure | Central region called the nucleus; consists of protons (positive) and neutrons (neutral) |
Electrons | Negatively charged particles that surround the nucleus; located in discrete energy levels called shells |
Chemical bonding | Formation of a compound by combining two or more elements |
Ionic bonding | Atoms gain or lose outermost valence electrons to form ions; ionic compounds consist of an orderly arrangement of oppositely charged ions |
Covalent bonding | Atoms share electrons to achieve electrical neutrality; covalent compounds are generally stronger than ionic bonds; both ionic and covalent bonds typically occur in the same compound |
Metallic bonding | Valence electrons are free to migrate amoung atoms; weaker and less common than ionic or covalent bonds |
Isotopes and radioactive decay | Mass number is the sum of neutrons plus protons in an atom; an isotope is an atom that exhibits variation in its mass number; some isotopes have unstable nuclei that emit particles and energy in a process known as radioactive decay |