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Mark S. Cracolice Edward I. Peters Mark S. Cracolice The University of Montana Chapter 6 Chemical Nomenclature
Metals, Nonmetals and Metalloids The stair-step line in the periodic table separates metals from nonmetals. Elements bordering this line are metalloids
Formulas of Elements For most elements, the smallest independent particle is an atom. The formula of the element is the elemental symbol. ElementFormula Helium He Lithium Li
Formulas of Elements Seven elements form stable diatomic molecules
Compounds of Two Nonmetals Binary Molecular Compound A compound formed by two nonmetals or a metalloid and a nonmetal.
Compounds of Two Nonmetals Naming Binary Molecular Compounds The first word is the name of the first element. A prefix is used to indicate the number of atoms. The second word is the name of the second element, changed to end in –ide. A prefix is used to indicate the number of atoms.
Compounds of Two Nonmetals Number prefixes used in chemical names NumberPrefixNumberPrefix 1mono- 6hexa- 2di- 7hepta- 3tri- 8octa- 4tetra- 9nona- 5penta- 10deca-
Compounds of Two Nonmetals Write the name of N 2 O 5. N = nitrogen; 2 = di The first word is dinitrogen O = oxygen, Change oxygen to end in -ide: oxide; 5 = penta The second word is pentoxide (the letter a in prefixes is omitted if the resulting word sounds better) dinitrogen pentoxide
Compounds of Two Nonmetals Write the formula of nitrogen trifluoride. No prefix on the first word, so mono- is implied = 1 atom. The symbol of nitrogen is N. Tri- prefix on the second word = 3 atoms. -fluoride is an “-ide modified” fluorine = F. NF 3
Compounds of Two Nonmetals Two compounds are so common they are always called by their traditional names: H 2 O is water NH 3 is ammonia
Ions, Cations, Anions Ion Charged particle formed when a neutral atom or molecule loses or gains electrons. Cation Positively charged ion. Anion Negatively charged ion.
Ions formed by One Element The charge on a main-group (U.S. A group) ion corresponds to its group number: Group1A2A3A5A6A7A Charge –2–1–
Ions Formed by One Element
Name of a monatomic cation Name of element, followed by the word ion. Name of a monatomic anion Name of element changed to end in -ide, followed by the word ion.
Ions Formed by One Element What is the formula of a sodium ion? Na +
Ions Formed by One Element What are the name and formula of the ion formed from a chlorine atom? Cl – Change the name chlorine to end in –ide. Chloride ion
Ions Formed by One Element Many transition elements (U.S. B groups) form multiple ions. The charge is shown by a Roman numeral enclosed in parentheses. Cr 2+ is the chromium(II) ion Cr 3+ is the chromium(III) ion
Ions Formed by One Element Some transition element ions always occur with only one charge Zn 2+ is zinc ion Ag + is silver ion Ni 2+ nickel ion Special Case Hg 2 2+ is called mercury(I) ion.
Acids and Their Anions Acid Molecular compound that reacts with water to produce a hydrated hydrogen ion and an anion. Ionization of hydrochloric acid HCl H 2 O + HCl → H 3 O + + Cl – H 3 O + is called hydronium ion.
Acids and Their Anions The Acids of Chlorine and Their Anions # of O atomsAcid prefixAnion prefix Compared withand/or suffixand/or suffix -ic acid and -ate anion(Example)(Example) One moreper- -icper- -ate HClO 4 (perchloric)(perchlorate) Same -ic -ate HClO 3 (chloric)(chlorate) One fewer -ous -ite HClO 2 (chlorous)(chlorite) Two fewerhypo- -oushypo- -ite HClO(hypochlorous)(hypochlorite) No oxygenhydro- -ic -ide HCl(hydrochloric)(chloride)
Acids and Their Anions The names and formulas of following acids should be memorized AcidIonization EquationIon Name Chloric acidHClO 3 H + + ClO 3 – Chlorate ion Nitric acidHNO 3 H + + NO 3 – Nitrate ion Sulfuric acidH 2 SO 4 2 H + + SO 4 2– Sulfate ion Carbonic acidH 2 CO 3 2 H + + CO 3 2– Carbonate ion Phosphoric acidH 3 PO 4 3 H + + PO 4 3– Phosphate ion
Acid Anions Step-by-Step Acid Anion Nomenclature H 3 PO 4 phosphoric acid H 2 PO 4 – dihydrogen phosphate ion HPO 4 2– hydrogen phosphate ion PO 4 3– phosphate ion
Acids and Their Anions
Formulas of Ionic Compounds Ionic Compound A compound made up of ions. The formula unit must have an equal number of positive and negative charges.
Formulas of Ionic Compounds Formula of the cation, followed by the formula of the anion. (omit the charges). Subscripts are used to show the number of each ion in the formula unit. (sum of charges must equal to zero) Omit the subscript if only one ion is needed. Enclose formula of the polyatomic ion in parentheses and place the subscript after the closing parentheses.
Formulas of Ionic Compounds What is the formula of magnesium chloride? Magnesium is in Group 2A, so its ion is Mg 2+. Chlorine is in Group 7A, so its ion is Cl –. Two 1– ions are needed to balance the 2+ ion. MgCl 2.
Formulas of Ionic Compounds What is the formula of barium nitrate? Barium cation is Ba 2+ Nitrate anion is NO 3 – Nitrate ion must be enclosed in parentheses Ba(NO 3 ) 2
Other Acids and Ions Memorize the following common and important ions: Hydroxide ionOH – Ammonium ionNH 4 +
Names of Ionic Compounds Example: Write the name of Zn(NO 3 ) 2. Solution: Zinc ion has only one common charge, 2+, so the magnitude of the charge is not included in its name: zinc ion. NO 3 – comes from the memorized acid HNO 3, nitric acid. To name the ion, the -ic ending changes to -ate: nitrate ion. Zinc nitrate
Names of Ionic Compounds How to Write the Name of an Ionic Compound 1. Write the name of the cation. 2. Write the name of the anion.
Names of Ionic Compounds Write the name of CoCl 2. There is more than one common charge for cobalt ions. We will have to use the anion to determine this charge. Chlorine is in Group 7A, so the charge on the ion is 1–: Cl –. The name of the anion is changed to end in -ide: chloride ion. Two 1– ions require a 2+ ion to balance the charge: cobalt(II) ion. Cobalt(II) chloride
Hydrates Hydrate A solid compound that includes water molecules as part of its crystal structure.
Hydrates Water of crystallization Water molecules that are part of the crystal structure in a hydrate. Anhydrous compound An ionic compound without water.
Hydrates Formulas of Hydrated Compounds Formula of ionic compound, followed by the number of water molecules, separated by a dot. Example: Copper (II) sulfate pentahydrate CuSO 4 5 H 2 O There are five water molecules for every formula unit of copper (II) sulfate.
Hydrates Names of Hydrated Compounds Use the prefixes for naming binary molecular compounds to indicate the number of water molecules associated with each formula unit of the anhydrous compound. Example: MgSO 4 7 H 2 O Magnesium sulfate heptahydrate
Hydrates Example: What is the formula of iron(III) sulfate nonahydrate? Solution: Iron(III) ion is Fe 3+. Sulfuric acid is H 2 SO 4, so sulfate ion is SO 4 2–. Nona- is the prefix for 9. -hydrate refers to water of hydration, H 2 O. 2 × 3+ balances 3 × 2–. Fe 2 (SO 4 ) 3 9 H 2 O
Homework Homework for chapter 6: 3, 5, 9, 13,15, 19, 21, 23, 25, 33, 35, 39, 41,43, 45, 47, 49 Fill the tables 6-13, 6-14, 6-15 and 6-16