This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Study Guide Ch 8, 9, 11 Chapter 8- Ionic, Covalent, and Polar Covalent Bonds Ionic Bond-forms when one or more valence electrons is transferred from one atom to another, creating positive and negative ions. Covalent Bond-involves sharing of valence electrons between atoms Polar covalent bonding-a bond in which the two atoms have residual or partial charges. COVALENT BONDS ARE COMPOSED OF ONLY NONMETAL ATOMS! IONIC COMPOUNDS ARE COMPOSED OF METAL + NONMETAL ATOMS!- Drawing Lewis Electron Dot Structures Covalent bonding is when a bond results when one or more electron pairs are shared between two atoms (can be represented by dots or a line). The bond representation is called a Lewis Structure when done in that fashion. Bond pair-the electron pair that is shared. Lone pair, or nonbonding electrons-not involved in bonding. Each molecule that is formed has a share in four pairs of electron (2 electrons only for hydrogen) so each has achieved a noble gas configuration. Each atom is surrounded by an octet of eight electrons. Constructing Lewis structures: 1. Determine the arrangement of atoms within a molecule (central atom is usually the one with the lowest electron affinity (often C, N, P, S) (halogens are often terminal atoms except when combined with O)). 2. Determine the total number of valence electrons in the molecule or ion (in neutral atom this is the sum of valence electrons for each atom) (for anion add the number of electrons equal to the negative charge) (for cation subtract the number of electrons equal to the positive charge). 3. Place one pair of electrons between each pair of bonded atoms to form a single bond. 4. Use any remaining pairs as lone pairs around each terminal atom (except hydrogen) so that each terminal atom is surrounded by eight electrons. 5. If the central atom has fewer than eight electrons at this point, change one or more of the lone pairs on the terminal atoms into a bonding pair between the central and terminal atom to form a multiple bond (double or triple bonds often occur when the atoms are either C, N, or O).- Octet Rule and Exceptions Octet Rule-the tendency of molecules and polyatomic ions to have structures in which 8 electrons surround each atom. Compounds in Which an Atom Has Fewer Than Eight Valence Electrons Boron has 3 valence electrons and forms three covalent bonds with other nonmetallic elements. This results in a valence shell for boron in its compounds with only six electrons, two short of an octet. The boron atom can accommodate a fourth electron pair when that pair is provided by another atom. If a bonding pair of electrons originates on one of the bonded atoms, the bond is called a coordinate covalent bond and its often represented by an arrow that points away from the atom donating the electron pair....
View Full Document