GEOL 1301 1st Edition Lecture 6Outline of Last Lecture I.Plate Tectonicsa.Driven by mantle convectionII.Subduction ZonesOutline of Current LectureCurrent LectureIII. MineralIV. Atomic bondsa. Ionicb. CovalentWhat is a mineral? Minerals, the building blocks of rocks, are naturally occurring, usually inorganic solids with specific crystal structures and chemical compositions. A mineral is constructed of atoms, the small units of matter that combine in chemical reactions. An atom is composed of a nucleus made up of protons and neutrons and surrounded by electrons. The atomic number of an element is the number of protons in its nucleus, and its atomic mass is the sum of the masses of its protons andneutrons.How do atoms combine to form the crystal structures of minerals? Chemical elements react with one another to form compounds either by gaining or losing electrons to become ions or by sharing electrons. Ionic bonds, which form by electrostatic attraction between positive ions (cations) and negative ions (anions), are the dominant type of chemical bond in mineral structures. Atoms thatform compounds by sharing electrons are held together by covalent bonds. When a mineral crystallizes, atoms or ions come together in the proper proportions to form a crystal structure—an orderly three-dimensional array in which the basic arrangement of the atoms is repeated in all directions.atomic mass: The sum of an atom’s protons and neutrons.atomic number: The number of protons in the nucleus of an atom.Cation: A positively charged ion. (Compare anion.)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.covalent bond: A bond between atoms in which electrons are shared. (Compare ionic bond.)ion: An atom or group of atoms that has an electrical charge, either positive or negative, because of the loss or gain of one or more electrons.ionic bond: A bond formed by electrostatic attraction between ions of opposite charge when electrons are transferred. (Comparecovalent bond.)metallic bond: A type of covalent bond in which freely mobile electrons are shared and dispersed among ions of metallic elements, which have the tendency to lose electrons and pack together ascations.mineral: A naturally occurring, solid crystalline substance, generally inorganic, with a specific chemical
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