Chemistry 2

• Atoms are represented using the element symbol and dots for valence electrons in Lewis Dot Structures
• Two shared electrons equal one bond
• Cations (positive ions) have Lewis structures without valence electrons
• Anions (negative ions) have Lewis structures with 8 valence electrons
• Valence electrons are capable of moving from one atom to another
• Core electrons cannot move and are pounded through the atom by the nucleus
• The Octet Rule states that 8 total valence electrons are needed to achieve stability
• Valence Shell is the outermost shell of an atom
• Ionic Bonding involves a total transfer of one or more electrons from one atom to another
• Ionic Compounds are composed entirely of ions and are electrically neutral
• Covalent Bonding involves sharing electrons and happens between non-metals
• In Covalent Bonding, atoms share an electron pair to achieve a noble gas configuration
• Metallic Bonding involves an "Electron Sea" where atoms share electrons to acquire stable electron configurations
• Empirical Formula shows the relative numbers of atoms in a compound
• Molecular Formula shows the exact formula of the compound
• Structural Formula identifies which atoms are bonded to which in a molecule
• Nonpolar Covalent Bonds have shared electrons equally and symmetrical electron density
• Polar Covalent Bonds have shared electrons unequally and asymmetrical electron density, resulting in partial charges (dipole)
• Electronegativity is the attraction an atom has for a shared pair of electrons
• Electronegativity trend increases up and to the right in the periodic table
• Ionic bonds have an electronegativity difference greater than 1.7
• Polar Covalent bonds have an electronegativity difference between 0.4 and 1.7
• Nonpolar Covalent bonds have an electronegativity difference less than 0.4