Chapter 2. The Components of Matter

Transcription

1 Chapter 2. The Components of Matter 1 The Periodic Table (Section 2.6) 13 Al Main Idea: 1. Groups: Old numbering system: New IUPAC numbering system: 2. Periods: 3. Know the names and properties of these groups: Alkali Metals Alkaline Earth Metals

2 Halogens 2 Chalcogens (also called The Oxygen Family ) Noble Gases 4. Be able to locate the stair-step line separating metals from nonmetals. 5. Identify and define metalloids. 6. Properties of metals: Properties of nonmetals: The Composition of Matter (Sections 2.1 and 2.9) Review these terms: Matter ---anything that occupies space and has mass; three phases of matter: solid, liquid, gas heterogeneous mixture--has nonuniform composition homogeneous mixture--uniform composition (solution) mixture--can be separated into simpler substances by physical means (e.g., filtration, distillation, chromatography) substance--generally refers to matter which is pure and has a fixed composition compound--can be decomposed into simpler substances by chemical means element--cannot be decomposed into simpler substances by chemical means intensive property--a property that is independent of the amount of material considered (e.g., density) extensive property--a property that depends on the amount of material considered (e.g., mass or volume) Matter Mixtures Pure Substances Heterogeneous Homogeneous Compounds Elements

3 Basic Atomic Structure (Section 2.5) 3 Subatomic particle abbreviation mass charge 1. Modern view of atomic structure: The volume of an atom is determined by and is mostly. Most of the mass of an atom lies in the which is extremely. 2. Important: When we use the term atom, we are emphasizing that atom: ion: 3. Know these terms: Atomic number Mass number Isotopes 4. Element Symbol: Examples: 12 C 13 C 14 C 31 P 3 23 Na + #p = #p = #p = #p = #p = #n = #n = #n = #n = #n = #e = #e = #e = #e = #e =

4 Nomenclature (Sections 2.7 and 2.8) 4 Ionic vs. Molecular Compounds In order to correctly name a compound, you must first determine if the compound is ionic or molecular. Ionic Compounds: Molecular Compounds: Example: Determine if the compounds below are ionic or molecular. PCl 3 SO 2 PH 3 MgBr 2 HBr CuCl 2 KF Fe 2 O 3 C 6 H 6 CS 2 NaCl LiBr Naming Cations 1. Monatomic Cations the name is the same as the name of the element Na Na + Charge of Group 1 Ca Ca 2+ Charge of Group 2 Al Al 3+ Charge of Group 3 2. Some transition metals form more than one cation: Two ways to name: Fe 2+ Fe 3+ Cu + Cu 2+ or or or or Just use the Roman numerals. You don t have to know ferric and cupric. Be sure to know the formula and charge of the zinc and silver cations:

5 3. Know three polyatomic cations: 5 Ammonium _ Mercury(I) _ Hydronium _ This is easy to remember, because the formula for ammonia is. Example: Give the formula and charge for each of the following cations. magnesium sodium hydrogen ammonium aluminum calcium Remember: Metals tend to lose electrons and become positively charged cations. Non-metals tend to gain electrons and become negatively charged anions. Naming Anions 1. Monoatomic Anions change the element ending to -ide Cl Cl Charge of Group 7 anions: O O 2 Charge of Group 6 anions: N N 3 Charge of Group 5 anions: 2. Four polyatomic anions ending in -ide : hydroxide cyanide peroxide azide 3. Six important anions: carbonate nitrate chlorate phosphate hydroxide sulfate

6 If you memorize nitrate and sulfate, then you also know nitrite and sulfite. (One fewer oxygen atoms, but the same charge: 6 sulfate ClO 4 sulfite ClO 3 nitrate ClO 2 nitrite ClO 4. Create a new polyatomic anion by adding to a highly charged ( _) anion: 2 SO 4 2 CO 3 2 SO 3 3 PO 4 H 2 PO 4 _ HSO 4 _ HCO 3 _ HSO 3 _ 2 HPO 4 5. Know the name, formula, and charge of each of the following polyatomic anions: acetate CH 3 COO nitrate NO 3 carbonate 2 CO 3 nitrite NO 2 hydrogen carbonate (bicarbonate) HCO 3 permanganate MnO 4 chlorate ClO 3 phosphate 3 PO 4 perchlorate ClO 4 hydrogen phosphate 2 HPO 4 chromate 2 CrO 4 dihydrogen phosphate H 2 PO 4 cyanide CN sulfate 2 SO 4 dichromate 2 Cr 2 O 7 hydrogen sulfate (bisulfate) HSO 4 hydroxide OH sulfite 2 SO 3 Names and Formulas of Ionic Compounds Two important principles: 1. The name of an ionic compound is just the name of the cation followed by the name of the anion. Do not use number prefixes, like di- tri- or tetra-. For example, MgCl 2 is magnesium chloride, not magnesium dichloride. 2. The overall formula for an ionic compound must be electrically neutral. That is, the number fo positive charges must equal the number of negative charges.

7 Examples: Give the formulas of the following ionic compounds: 7 magnesium chloride calcium chloride aluminum oxide calcium hydroxide sodium nitrate magnesium sulfide calcium nitrite ammonium chloride iron (III) bromide ammonium phosphate potassium hydroxide calcium carbonate aluminum sulfate aluminum carbonate magnesium sulfite ammonium sulfate Examples: Name the following compounds: K 2 SO 3 NaNO 2 Cu(NO 3 ) 2 KCl FeO Ag 2 SO 4 Fe 2 O 3 (NH 4 ) 3 PO 4 Naming Binary Molecular Compounds These consist of two nonmetal elements. Two rules: 1) Name the more positive element first, then the more negative element with an -ide ending 2) Use numeric prefixes (mono-, di-, tri-, tetra-, penta-, etc.) when the two elements form more than one binary compound. However, don t use mono on the first element, and don t use any number prefixes if the first element is hydrogen. (If the first element is hydrogen, name it as if it were ionic.)

8 Examples: Name the following compounds. 8 HCl(g) PCl 5 SO 2 N 2 O 5 SO 3 CCl 4 PCl 3 CS 2 Naming Acids An acid will consist of combined with. Examples: Give the formulas for the acids containing the anions listed below: Cl CO 3 2 SO 4 2 S 2 NO 3 PO 4 3 Key principle: The name of an acid is determined by the name of the anion. 1. If the acid is formed from an anion ending in -ide : Examples: Cl - HCl CN - HCN S 2- H 2 S 2. If the acid is formed from an anion ending in -ate : Examples: SO 4 2 NO 3 ClO 4 CH 3 COO H 2 SO 4 HNO 3 HClO 4 CH 3 COOH

9 3. If the acid is formed from an anion ending in -ite : 9 Examples: NO 2 HNO 2 SO 3 2 H 2 SO 3 ClO 2 HClO 2 ClO HClO, also written as: 4. Be careful!! Some substances are named as molecular compounds in their pure (usually gaseous) form, and as acids when dissolved in aqueous solutions: H 2 S(g) H 2 S(aq) HCN(g) HCN(aq) HCl(g) HCl(aq) Diatomic Molecules There are seven elements which exist as diatomic molecules in their naturally occurring form. You must know these elements. H 2 N 2 O 2 F 2 Cl 2 Br 2 I 2