Understanding Chemical Bonds: Definitions and Molecular Shapes

Chemical Bonding and Molecular Structure

• • Ionic Compound: A chemical substance composed of positive and negative ions.
  • Crystal: A solid with flat faces that form sharp angles, whose atoms, ions, or molecules are arranged in a regular three-dimensional arrangement.
  • Double Bond: A covalent bond in which two pairs of electrons are shared between two atoms.
  • Electronegativity: The attraction an atom in a molecule exerts on the electrons of a covalent bond.
  • Electronegative Element: Elements, particularly fluorine, oxygen, and nitrogen, have a very strong attraction for the electrons involved in chemical bonding.
  • Covalent Bond: An electron pair shared between two atoms in a molecule.
  • Nonpolar Covalent Bond: A chemical bond in which one or more pairs of electrons are shared equally between two atoms of the same element.
  • Polar Covalent Bond: A covalent bond in which electrons are shared unequally due to differences in electronegativity between atoms linked by the bond.
  • Ionic Bond: The attraction between oppositely charged ions.
  • Metallic Bond: A bond between metal atoms to form solid elements.
  • Single Bond: A covalent bond in which a pair of electrons is shared between two atoms.
  • Coordinate Covalent Bond: A chemical bond formed when one atom donates two electrons that are shared in a covalent bond.
  • Chemical Bond: Attractive forces that hold atoms or ions together in a chemical compound.
  • Resonance Structure: Two or more Lewis structures with the same arrangement of atoms but different arrangements of electrons.
  • Angular (Bent): An unbalanced arrangement of atoms in a molecule, in which the atoms are not linked in a linear array (ABA).
  • Trigonal Pyramidal Shape: An arrangement of atoms bonded to a central atom, in which the four atoms do not lie in a plane.
  • Linear Form: An arrangement of atoms in a molecule in which these are linked to each other in a straight line.
  • Molecule: Two or more atoms held together by covalent chemical bonds that form an electrically neutral entity, so that the molecule behaves as a single particle with a neutral electric charge.
  • Shared Electron Pair: A pair of electrons involved in a covalent bond.
  • Hydrogen Bridges: Intense attraction between molecules that have a hydrogen atom covalently bound to an atom of fluorine, oxygen, or nitrogen.
  • Octet Rule: The tendency of a metal atom to gain or share electrons to have eight valence electrons.
  • Valence Shell Electron Pair Repulsion (VSEPR) Theory: A theory that can predict the shape of a molecule by examining the structure that is created when all pairs of valence electrons surrounding a central atom in a molecule repel each other and remain as far apart as possible.
  • Tetrahedral: A molecule with this shape has four atoms located at the four corners of a tetrahedron bound to a central atom, forming angles of 109°.
  • Trigonal Planar: An arrangement of three atoms attached to a central atom so that the four atoms lie in one plane, forming three angles of 120° each.
  • Triple Bond: A covalent bond in which three pairs of electrons are shared between two atoms.