1 / 29

Chemical Nomenclature

“Chemical Nomenclature as we know it is born with the publication of Méthode de nomenclature chimique by Antoine-Laurent Lavoisier, Claude-Louis Berthellot,

paul2
Télécharger la présentation

Chemical Nomenclature

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. “Chemical Nomenclature as we know it is born with the publication of Méthode de nomenclature chimique by Antoine-Laurent Lavoisier, Claude-Louis Berthellot, Antoine de Fourcroy, and Guyton de Morveau. The names proposed were based on the elements origin or function. (Image produced courtesy of the Library & Information Centre, Royal Society of Chemistry)” Chemical Nomenclature http://www.rsc.org/chemsoc/timeline//pages/1787.html CHM 1010 PGCC Barbara Gage

  2. Chemical Nomenclature • System of rules for naming pure substances • Elements – element name used even if the substance is di- or polyatomic O2 = oxygen S8 = sulfur • Compounds - naming differs depending on whether a substance is held together primarily by ionic or covalent bonds. CHM 1010 PGCC Barbara Gage

  3. Ions… • Electrons are arranged on levels or “shells”. Atoms are most stable with 8 electrons on their outermost shell. This is often referred to as the octet rule. • Number of electrons on the outer shell = Group number for elements in Groups I-VIII A (using the US convention labeling on periodic table) CHM 1010 PGCC Barbara Gage

  4. Figure 2.10 The modern periodic table. US Convention IUPAC Convention CHM 1010 PGCC Barbara Gage Silberberg, Principles of Chemistry

  5. Ions… • To achieve the octet, atoms with more than 4 electrons on the outer shell will gain enough electrons to reach 8. • Cl Group 7 7 electrons on outer shell Cl will gain 1 e- . • Now #e- = 18 but #p+ = 17 so the chlorine is an ion with the formula Cl1-. CHM 1010 PGCC Barbara Gage

  6. Ions… • O Group 6 6 electrons on outer shell O will gain 2 e- . • Now #e- = 10 but #p+ = 8 so the oxygen is an ion with the formula O2-. • P Group 5 5 electrons on outer shell P will gain 3 e- • Now #e- = 18 but #p+ = 15 so the phosphorus is an ion with the formula P3- CHM 1010 PGCC Barbara Gage

  7. Ions… • Na Group 1 1 electron on outer shell O will lose 1 e- to expose the complete inside shell. • Now #e- = 10 but #p+ = 11 so the sodium is an ion with the formula Na1+. • Mg Group 2 2 electrons on outer shell Mg will lose 2 e- • Now #e- = 10 but #p+ = 12 so the magnesium is an ion with the formula Mg2+ CHM 1010 PGCC Barbara Gage

  8. -- 1+ 2+ 3+ -- 3- 2- 1- Generally metals form cations and non-metals form anions. CHM 1010 PGCC Barbara Gage

  9. Binary Ionic Compounds • Cations(positively charged ions)and anions (negatively charged ions) will associate with each other and form a neutral binary compound to reduce energy . • 1 Na+ 1 Cl-NaCl • 1 Ca2+ 1 O2-CaO • 3 K+ 1 N3- K3N • 2 Al3+ 3 S2- Al2S3 CHM 1010 PGCC Barbara Gage

  10. Naming binary ionic compounds The name of the cation (positively charged ion) is written first, followed by that of the anion. The name of the cation is the same as the name of the metal. Many metal names end in -ium. The name of the anion (negatively charged ion) takes the root of the nonmetal name and adds the suffix -ide. Calcium and oxygen form calcium oxide. Aluminum and sulfur form aluminum sulfide. CHM 1010 PGCC Barbara Gage

  11. Naming Ionic Binary Compounds CHM 1010 PGCC Barbara Gage

  12. PROBLEM: Name the ionic compound formed from the following pairs of elements: Naming Binary Ionic Compounds (a) magnesium and nitrogen (b) iodine and cadmium (c) strontium and fluorine (d) sulfur and potassium PLAN: Use the periodic table to decide which element is the metal and which the nonmetal. The metal (cation) is named first and we use the -ide suffix on the nonmetal name root. SOLUTION: (a) magnesium nitride (b) cadmium iodide (c) strontium fluoride (d) potassium sulfide CHM 1010 PGCC Barbara Gage From Silberberg, Principles of Chemistry

  13. PROBLEM: Write simplest formulas for the compounds named in Sample Problem 2.5. Determining Formulas of Binary Ionic Compounds PLAN: Compounds are neutral. We find the smallest number of each ion which will produce a neutral formula. Place subscripts to the right of the element symbol. SOLUTION: (a) Mg2+ and N3-; three Mg2+(6+) and two N3-(6-); Mg3N2 (b) Cd2+ and I-; one Cd2+(2+) and two I-(2-); CdI2 (c) Sr2+ and F-; one Sr2+(2+) and two F-(2-); SrF2 (d) K+ and S2-; two K+(2+) and one S2- (2-); K2S CHM 1010 PGCC Barbara Gage

  14. Binary Ionic Compounds • The “B” group elements may form cations with more than one charge. • To specify which cation forms a compound, a roman numeral equal to the charge is added to the cation name. Fe2+ = iron (II) Fe3+ = iron (III) CHM 1010 PGCC Barbara Gage

  15. CHM 1010 PGCC Barbara Gage

  16. PROBLEM: Give the systematic names for the formulas or the formulas for the names of the following compounds: (a) tin(II) fluoride (b) CrI3 (c) manganese (IV) sulfide (d) CrO3 Sample Problem 2.7 Determining Names and Formulas of Ionic Compounds of Elements That Form More Than One Ion PLAN: Compounds are neutral. We find the smallest number of each ion which will produce a neutral formula. Use subscripts to the right of the element symbol. SOLUTION: (a) Tin (II) is Sn2+; fluoride is F-; so the formula is SnF2. (b) The anion I is iodide(I-); 3I- means that Cr(chromium) is +3. CrI3 is chromium(III) iodide (c) Manganese (IV) is Mn2+; oxide is S2-, therefore the formula is MnS2. (d) Cr is chromium; the anion O is oxide(2-); the compound is cobalt (VI) oxide. CHM 1010 PGCC Barbara Gage Modified from Silberberg, Principles of Chemistry

  17. Polyatomic Ions • Some atoms form bonds that hold atoms together in a structure that has an overall charge (rather than as a neutral compound. These ions are called polyatomic ions. • CO32- carbonate SO42- sulfate • Compounds with polyatomic ions are named with the cation and anion name. • Na2SO4 – sodium sulfate CHM 1010 PGCC Barbara Gage

  18. CHM 1010 PGCC Barbara Gage

  19. PROBLEM: Give the systematic names or the formula or the formulas for the names of the following compounds: Determining Names and Formulas of Ionic Compounds Containing Polyatomic Ions (a) Fe(ClO4)2 (b) sodium sulfite PLAN: Note that polyatomic ions have an overall charge so when writing a formula with more than one polyatomic unit, place the ion in a set of parentheses. SOLUTION: (a) ClO4- is perchlorate; iron must have a 2+ charge. This is iron(II) perchlorate. (b) The anion sulfite is SO32- therefore you need 2 sodiums per sulfite. The formula is Na2SO3. CHM 1010 PGCC Barbara Gage

  20. Prefix Prefix Prefix Number Number Number 1 mono 4 tetra 8 octa 2 di 5 penta 9 nona 3 tri 6 hexa 10 deca Hydrates • Some compounds have water molecules attached as part of their structure. These are termed hydrates. • CuSO4. 5H2O copper (II) sulfate pentahydrate Numerical Prefixes for Hydrates and Binary Covalent Compounds CHM 1010 PGCC Barbara Gage

  21. Binary Acids • When certain binary gases dissolve in water they form acids with the same formula. The name is changed to add –ic acid to the anion HCl (g)  HCl (aq) hydrogen chloride hydrochloric acid CHM 1010 PGCC Barbara Gage

  22. Binary Acids • HF (aq) hydrofluoric acid • HCl (aq) hydrochloric acid • HBr (aq) hydrobromic acid • HI (aq) hydroiodic acid • HCN (aq) hydrocyanic acid CHM 1010 PGCC Barbara Gage

  23. Oxyacids • Acids containing oxygen; most do not exist in the same form without water HNO3 nitric acid HNO2 nitrous acid H2SO4 sulfuric acid H2CO3 carbonic acid H3PO4 phosphoric acid HC2H3O2 or CH3COOH acetic acid CHM 1010 PGCC Barbara Gage

  24. Covalent Binary Compounds • Non-metals form bonds by sharing electrons rather than transferring them. • The resulting bond is referred to as a covalent bond. • The element farthest to the left or lower on the periodic table is generally written first. Subscripts are replaced by numerical prefixes in the name. CHM 1010 PGCC Barbara Gage

  25. Covalent Binary Compounds • CO2 carbon dioxide • N2O dinitrogen oxide • P2S5diphosphoruspentasulfide • SiCl4 silicon tetrachloride • For compounds where two vowels occur together when the prefix is added, the vowel from the prefix can be dropped (except for iodine). • N2O5 dinitrogenpentaoxide CHM 1010 PGCC Barbara Gage

  26. Naming Binary Covalent Compounds CHM 1010 PGCC Barbara Gage

  27. PROBLEM: SOLUTION: Determining Names and Formulas of Binary Covalent Compounds (a) What is the formula of carbon disulfide? (b) What is the name of PCl5? (a) Carbon is C, sulfide is sulfur S and di-means 2 - CS2. (b) P is phosphorus, Cl is chloride, the prefix for 5 is penta-. Phosphorus pentachloride. CHM 1010 PGCC Barbara Gage

  28. CHM 1010 PGCC Barbara Gage

More Related