110 likes | 220 Views
Binary Molecular (Covalent) Compounds. Molecule: a neutral group of elements joined by a covalent compound Diatomic Molecule: A molecule consisting of two atoms Diatomic Elements: (7 of them, form a 7 on the PT) and they end in –ine or gen (N, O, F, Cl, Br, I, H).
E N D
Molecule: a neutral group of elements joined by a covalent compound • Diatomic Molecule: A molecule consisting of two atoms • Diatomic Elements: (7 of them, form a 7 on the PT) and they end in –ine or gen (N, O, F, Cl, Br, I, H)
Molecular compound: Compound composed of molecules 1. Binary molecular compounds are made up of 2 elements • Typically these elements are nonmetals • There are no charges in a molecular compound • Molecular compounds are held together by covalent bonds
A covalent bond is a sharing of electrons so that each element forms an octet • We can show the sharing of e- by drawing Lewis structures (dot diagrams) • The first rule for drawing a molecular Lewis structure is to get the formula
Next, count the number of electrons • Each bond that is formed requires 2 electrons • We can show a single bond with 2 electrons or with 1 line • We can show a double bond with 4 e- or with 2 lines • We can show a triple bond with 6 e- or with three lines
Valence electrons that are shared b/w 2 elements are called bonding electrons • Valence e- that are not shared b/w 2 elements are called lone pair electrons • In the end, each element should always have/share 8 e-, except for H b/c this element can only have 2 e-
H2 • H2O • NH3
CO2 • N2 • HCN • SO3
16. A resonance structure is a structure that occurs when two or more valid electron dot structures are able to be drawn. • An arrow indicates multiple resonance structures. See page 224 in book
Examples: • SO3 • O3
Some elements form “expanded octets: in which more than 8 electrons can be had. Phosphorus and sulfur do this a lot! ex: SF6 and PCl5