Section 4 1 Naming Binary Compounds Forming Compounds

Section 4. 1 Naming Binary Compounds Forming Compounds • Atoms want to have an outer energy shell that contains 8 electrons (or that is completely full… i. e. H and He want 2, not 8) • Stable octet - presence of 8 electrons in the outermost energy level – Least reactive atoms have stable octets (Noble gases) – Most reactive atoms do not have stable octets

Section 4. 1 Naming Binary Compounds Forming Compounds • In order to achieve stable octets, atoms can form compounds if they: – gain or lose electrons to form ions, then the ions can attract to other ions forming ionic bonds. – These are called ionic compounds. OR – share electrons in covalent bonds. – These are called covalent compounds. • A chemical bond is a force that holds atoms together.

Section 4. 1 Naming Binary Compounds That Contain Ions • Ions combine to form ionic compounds. • Properties of ionic compounds – High melting points – Conduct electricity • If melted • If dissolved in water

Section 4. 1 Naming Binary Compounds That Contain Ions • electrically neutral. • made of a positive ion called a cation and a negative ion called an anion • total charge in the compound must = zero.

Section 4. 1 Naming Binary Compounds Quick definitions: • monatomic ion - cation or anion formed from a single atom. Examples: • polyatomic ion – cation or anion formed by more than one atom. Examples: • Ionic bond - bond formed by the attraction of oppositely charged ions • Ionic compound - chemical compound composed of cations and anions combined so that the total positive and negative charges are equal • Binary compound - contains two elements in the compound • Ternary compound - contains 3 elements in the compound

Section 4. 1 Naming Binary Compounds Type I—Representative Element Ionic Compounds • • Metal present forms only one possible cation How can you tell what the charge will be on the ion? … by the Oxidation Number! For representative elements, look at the columns 1, 2, 13, 14, 15, 16 and 17, on the Periodic Table. • Examples: Oxidation #

Section 4. 1 Naming Binary Compounds Nomenclature- system for naming chemical substances Nomenclature for ions- • Monatomic cations: (element name) + “ion” • Monatomic anion – (element name root) + “ide” + “ion” • Examples on next slide…

Section 4. 1 Naming Binary Compounds Naming Compounds That Contain a Metal and a Nonmetal Names of

Section 4. 1 Naming Binary Compounds Naming Compounds That Contain a Metal and a Nonmetal Type I—Representative Element Ionic Compounds

Section 4. 1 Naming Binary Compounds Naming Compounds That Contain a Metal and a Nonmetal • For compounds containing both a metal and a nonmetal, the metal is always named first. The nonmetal is named from the root element name.

Section 4. 1 Naming Binary Compounds TYPE I—Representative Element Ionic Compounds • Examples—Name the following: – – – Ca. Cl 2 K 2 S Mg. O Ca 3 N 2 Cs 3 P Now name the ones on your notes…

Section 4. 1 Naming Binary Compounds Type I—Representative Element Ionic Compounds: Writing Formulae • Write the cation element symbol and charge followed by the anion element symbol and charge. • Do the charges cancel each other? … the total charge MUST be zero. • Na+ and Cl- : These two ions have charges that cancel each other out. To get a total charge of zero, they need only be in a 1: 1 ratio. Therefore, the formula is simply: _______. • What is this compound called? _____ • Ba 2+ and 02 -: These two ions also have charges that cancel each other out. They are also in a 1: 1 ratio. What would the formula be? _____. • What is this compound called? ______

Section 4. 1 Naming Binary Compounds Type I Writing Formulae • Mg 2+ and Cl-: These two ions do not have charges that cancel each other out. What ratio will make the charges cancle? (Hint: CRISS CROSS!). • What would the formula be? _____. • What is this compound called? _____

Section 4. 1 Naming Binary Compounds Helpful Hints Superscripts describe charges on ions. • Once ions combine to form compounds the charges are NO LONGER needed in the formula. Subscripts describe the numbers of atoms it takes to complete that particular compound. • The subscript for an ion depends on the OTHER ION with which it is combined. All ionic formulae should be in the lowest whole number ratio.

Section 4. 1 Naming Binary Compounds Type II—Transition Metal Ionic compounds • • • Remember Type I (see below) Looking at the periodic table will not always predict charges. Transition metals form ions in more than one way. (They can have more than one oxidation number) Remember: transition metals are in the d-block of the PT

Section 4. 1 Naming Binary Compounds Type II Transition Metal Ionic compounds • Ex. : Gold can form Au+ or Au 3+ …so how are ions named if more than 1 charge is possible? • …USING Roman Numerals! • Name these two ions:

Section 4. 1 Naming Binary Compounds Type II Transition Metal Ionic compounds Follow the rules for nomenclature as before with Type I… • the only change will be that the name has a Roman Numeral between the cation and anion names • Since the metal ion can have more than one charge, a Roman numeral is used to specify the charge. • Au. Cl: gold (I) chloride • Au. Cl 3: Gold (III) Chloride

Section 4. 1 Naming Binary Compounds Type II Transition Metal Ionic compounds For determining the formula from given information: • the Roman Numeral tells you the charge on the cation. • Then, proceed as with Type I… • Since the metal ion can have more than one charge, a Roman numeral is used to specify the charge. • Au. Cl: gold (I) chloride • Au. Cl 3: Gold (III) Chloride

Section 4. 1 Naming Binary Compounds Type II Transition Metal Ionic Compounds ONLY use roman numerals with transition metals… Do the practice in your …plus lead and tin notes…

Section 4. 1 Naming Binary Compounds Exceptions to TYPE II Rules: Use Roman Numerals on all Transition metals EXCEPT: • Zinc (Zn), Silver (Ag), and Cadmium (Cd). Even though they aren’t ion the d-block, Roman Numerals must also be used on: • Tin (Sn) and Lead (Pb) because they show different oxidation states! Complete the examples in your notes…

Section 4. 1 Naming Binary Compounds Naming Compounds/Writing Formulae That Contain Polyatomic Ions • Polyatomic ions are charged entities composed of several atoms bound together. • They function as a single ion. • The charge applies to the whole ion--not just the last element • Use parentheses when you need more than one atom of the ion to complete a compound so the subscripts don’t get confusing…

Section 4. 1 Naming Binary Compounds Polyatomic Ions--Examples But you don’t need this chart if you’ve memorized your poly ions. In fact, this should be the easiest part of the unit for those of you who know them!!

Section 4. 1 Naming Binary Compounds Naming Compounds That Contain Polyatomic Ions • Naming ionic compounds containing polyatomic ions follows rules similar to those for binary compounds. – ammonium acetate Now do the practice on your notes!!

Section 4. 1 Naming Binary Compounds Type III—Covalent Compounds • • Covalent means: two non-metals No polyatomic ions The chemical bond is a sharing of electrons

Section 4. 1 Naming Binary Compounds • • • Type III—Covalent Compounds Diatomic molecules: these elements NEVER occur as single atoms. In elemental form, they always have two atoms bound together in a molecule. You must memorize these. H. Br. ONCl. IF or H plus “go to 7, make a 7…” Hydrogen: H 2 Bromine: Br 2 Oxygen: O 2 Nitrogen: N 2 Chlorine: Cl 2 Iodine: I 2 Fluorine: F 2

Section 4. 1 Naming Binary Compounds Type III—Covalent Compounds Summarized: Prefix+(Name of First Nonmetal) then Prefix+(Name of Second Nonmetal 1 st syllable)+”ide”

Section 4. 1 Naming Binary Compounds Type III—Covalent Compounds • Now complete the examples in your notes…

Section 4. 1 Naming Binary Compounds Naming Compounds: A Review

Section 4. 1 Naming Binary Compounds Naming Acids • An acid is a molecule with one or more H+ ions attached to an anion.

Section 4. 1 Naming Binary Compounds B. Naming Acids

Section 4. 1 Naming Binary Compounds Naming Acids summary…

Section 4. 1 Naming Binary Compounds Binary Compound? NO YES Is it an acid? (Does it contain H+ ion? ) NO Metal present? YES NO Covalent! TYPE III: use prefixes Recognize the polyatomic ions and name according to the ionic rules YES Metal forms more than one oxidation state? NO Representative! TYPE I: use element name only for cation Follow Acid naming rules YES Transition Metal!* TYPE II: use element name AND Roman Numeral for the cation