Practice PCl 5 dihydrogen monoxide SF 6 carbon trichloride N 2 Odisulfur hexoxide NO 2 nitrogen triiodide
Naming Acids An acid is any compound that starts with a hydrogen When naming an acid: –1 st locate the anion (- charge)
Acid Nomenclature If the anion in the acid ends in –ide (not PI) change the ending to -ic acid and add the prefix hydro- hydro________ic acid –HCl: hydrochloric acid
Acid Nomenclature If the anion in the acid ends in –ite (all PIs) change the ending to -ous acid. _________ous acid –HClO 2 : chlorous acid
Acid Nomenclature If the anion in the acid ends in –ate (all Pis) change the ending to -ic acid. ___________ic acid –HClO 3 : chloric acid I
Acids – Finishing Up If you have the name and need to find the formula –Example: Acetic Acid –Cross off the –ic and add at –ate –Acetate! = C 2 H 3 O 2 - Finish by adding the correct # of Hs (1 for every negative) HC 2 H 3 O 2 is acetic acid
Covalent Bonding Covalent bond – atoms share electrons. There are several electrostatic interactions in these bonds: –Attractions between electrons and nuclei –Repulsions between electrons –Repulsions between nuclei
Lewis Dot Structures ONLY Valence (outer) electrons are involved. Lewis dot structures can be drawn for: – atoms –molecules Lewis dot structures show structure of a molecule, and help predict shape.
Steps to Writing Lewis Structures 1.Find the sum of valence electrons of all atoms in the polyatomic ion or molecule. PCl 3 5 + 3(7) = 26
Writing Lewis Structures 2.Arrange element symbols to show how atoms are connected – show electrons as dots. Follow the octet rule except for hydrogen, which only needs two electrons to be full Connect the electrons as lines Keep track of the electrons: 26 - 6 = 20
Writing Lewis Structures 3.Fill the octets of the outer atoms. Keep track of the electrons: 26 - 6 = 20; 20 - 18 = 2
Writing Lewis Structures 4.Fill the octet of the central atom. 5.Finish by checking for octets. Keep track of the electrons: 26 - 6 = 20; 20 - 18 = 2; 2 - 2 = 0
Writing Lewis Structures 6.If you run out of electrons before the central atom has an octet… …form multiple bonds until it does.
Exceptions! Boron and Aluminum are okay with only 6 e - around them –BF 3
Exceptions If the Lewis Dot Structure you are drawing is an ion: – Use  and specify the charge –Add or subtract electrons Positive charges take away electrons Negative charges add electrons Example: Br -