Chapter 8 Review (Nicholas Delor)

Ionic vs Molecular Compounds

Both

Molecular

Groupings of atoms

Octet rule

Bonds

Compounds

2 or more nonmetals

Shares electrons

Gases/Liquids at room temp.

Atomic molecule Br2I2N2Cl2O2F2

Low melting point

Ionic

High melting point

Solids/molecular liquids at room temp.

Electricity conductor

Transfers electrons

Metal/Nonmetal

VSEPR Theory and Molecular Geometry

Tetrahedral (CH4)

Trigonal-pyramidal (NH3)

Bent or Angular (ONF)

Bent or Angular (H20)

Trigonal-planar (BF3)

Trigonal bipyramidal (PCl5)

Linear (BeF2)

Octahedral (SF6)

Definitions

Single Covalent Bond - Two atoms held together by sharing a pair of electrons.

Structural Formula - Represents the covalent bonds by dashes and shows the arrangement of covalently bonded atoms.

Octet Rule - In covalent bonds, electron sharing usually occurs so that atoms attain the electron configuration of noble gases. This can be either filling an element by having 2 or 8 valence electrons. Elements from the nonmetals and metalloids will combine to form covalent bonds.

Unshared pair - A pair of valence electrons that are not shared between atoms.

Lewis Dot Diagrams - Element Symbol surrounded by dots indicating the number of electrons in the outermost energy level of the atom (AKA, Valence Electrons).

Covalent Bond Variations

Double & Triple Covalent Bonds

Coordinate Covalent Bond - A covalent bond in which one atom contributes both bonding electrons. In a coordinate covalent bond, the shared electron pair comes from one of the bonding atoms.

Atoms form double or triple covalent bonds if they can attain a noble gas structure by sharing two pairs or three pairs of electrons.

Double Covalent Bond - A bond that involves two shared pairs of electrons.

Triple Covalent Bond - A bond that involves three shared pairs of electrons.

Electronegativity Values for Selected Elements

Hydrogen (H) - 2.1

Lithium (Li) - 1.0, Beryllium (Be) - 1.5, Boron (B) - 2.0, Carbon (C) - 2.5, Nitrogen (N) - 3.0, Oxygen (O) - 3.5, Fluorine (F) - 4.0

Sodium (Na) - 0.9, Magnesium (Mg) - 1.2, Aluminum (Al) - 1.5, Silicon (Si) - 1.8, Phosphorus (P) - 2.1, Sulfur (S) - 2.5, Chlorine (Cl) - 3.0

Potassium (K) - 0.8, Calcium (Ca) - 1.0, Gallium (Ga) - 1.6, Germanium (Ge) - 1.8, Arsenic (As) - 2.0, Selenium (Se) - 2.4, Bromide (Br) - 2.8

Rubidium (Rb) - 0.8, Strontium (Sr) - 1.0, Indium (In) - 1.7, Tin (Sn) - 1.8, Antimony (Sb) - 1.9, Tellurium (Te) - 2.1, Iodine (I) - 2.5

Caesium (Cs) - 0.7, Barium (Ba) - 0.9, Thallium (Tl) - 1.8, Lead (Pb) - 1.9, Bismuth (Bi) - 1.9