Ion formation: Writing formulae and names for ionic compounds. Having fun with nomenclature! element 1 Ca 2 electrons lost. nonmetallic.

Transcription

1 Ion formation: Symbol of Change in electrons element 1 Ca 2 electrons lost Formula of ion Name of ion Metallic or nonmetallic 2 F F 1-3 Al 3+ 4 Zn 2 electrons lost 5 O 2-6 Cs 1 electron lost 7 Ba electrons gained P 3-9 S S 2-10 In 11 Ga Se 2 electrons gained 13 F 1-14 Ra 2 electrons lost 15 H At 1 electron gained 17 N 3-18 Fe 2 electrons lost Writing formulae and names for ionic compounds. Elements Symbols Ion symbols Compound Formula Name 1 magnesium & fluorine 2 sodium & oxygen 3 aluminum & oxygen 4 zinc & chlorine 5 potassium & sulphur 6 calcium & chlorine 7 sodium & sulphur 8 aluminum & nitrogen 9 hydrogen & oxygen 10 lithium & nitrogen 1

2 Binary Compounds WRITING ELEMENT FORMULAS For hydrogen, halogens and noble gases The elements below form diatomic molecules. All can be solids, liquids or gases depending on the temperature and pressure. At room temperature and pressure, only bromine (liquid) and iodine (solid) are not gases. hydrogen nitrogen oxygen fluorine chlorine iodine bromine sulphur (S 8 ) phosphorus (P 4 ) WRITING COMPOUND FORMULAS It is a good idea to understand how the following chemicals were named in the first place. 1. The element with the lowest electronegativity was named first. 2. The suffix ide replaced the suffix of the second element. Follow the same steps as in the Zero Sum Rule, but do the work in your head. magnesium sulphide sodium sulphide calcium fluoride strontium oxide rubidium selenide aluminum chloride Barium bromide lithium iodide NAMING BINARY COMPOUNDS AND MULTI-ATOMIC ELEMENTS Ca 3 N 2 MgCl 2 Al 4 C 3 Al 2 O 3 Zn 2 Si SiH 4 KBr H 2 S Zn 3 S 2 Ag 3 P BaI 2 Al 2 O 3 I 2 Ne Kr N 2 BINARY IONIC COMPOUNDS TRANSITION METALS WRITING FORMULAS When given STOCK SYSTEM names As you may know from Grade 10, some metal ions have more than one possible ion charge. For example, chromium atoms can lose two, three, or six electrons to become Cr 2+, Cr 3+, or Cr 6+ ions. The most common ion charges are listed on your periodic table. The Stock System uses Roman numerals to show the ion charge of the metal ion when naming a particular compound. For example, the two common chromium ions are chromium (II) and chromium (III). Each of these ions may bond to form unique chromium compounds such as chromium (II) chloride or chromium (III) chloride. **In order to avoid confusion please remember: Roman numerals (the Stock System) are NOT used for metal ions that have only one ion charge. lead (II) sulphide iron (III) oxide nickel (II) chloride iron (III) oxide **zinc phosphide chromium (II) phosphide Cobalt (II) iodide tin (IV) bromide lead (II) iodide **silver nitride 2

3 WRITING FORMULAS WHEN GIVEN SUFFIX (OLD) SYSTEM NAMES (NOTE: you do not have to know the old system of naming, only the Stock system) Before beginning this section, consider how the compounds were named in the first place. The suffix system is used to name ions that have TWO possible ion charges. The suffix ous refers to the lower and ic the higher of the two ion charges. For example, iron atoms can lose either two or three electrons to form Fe 2+ or Fe 3+ ions. Using the stock system the ions are iron (II) or iron (III). Using the suffix system these ions are written ferrous and ferric. Each of these iron ions may bond to form unique compounds such as ferrous oxide or ferric oxide. auric chloride cuprous bromide antimonic carbide cupric oxide NAMING USING THE STOCK SYSTEM FeCl 2 Sb 2 S 5 SnO 2 SnF 2 CuBr Hg 2 O FeCl 3 Pb 3 N 4 CrCl 3 FeS CuCl 2 Mn 3 P 2 CuO Zn 3 P 2 CdS Sb 2 S 3 FeO VCl 5 Fe 2 O 3 Sb 2 S 5 Cu 2 S SnF 4 cobaltous oxide ferrous sulphide stannous oxide mercuric oxide SIMPLE IONIC COMPOUNDS WITH POLYATOMIC IONS (IONS WITH MORE THAN ONE ATOM) Polyatomic ions are groups of atoms that have achieved a stability of their own and exist as a group. Since the group is not an individual atom, we must give it a different name. These names are found in the weird chart on the back of your periodic table or in your textbook. Anytime you see a compound with more than two elements in it, you know it must have a polyatomic ion in it! OLD SYSTEM - THEN WHY DO WE HAVE TO KNOW IT? When oxygen atoms are gained or removed from an oxygen-containing polyatomic ion, the name of the ion reflects the change. per ate (greatest number of oxygen atoms e.g. perchlorate ClO 1-4 (Group 17 only)) ate (greater number of oxygen atoms than ite e.g. sulphate SO 2-4, chlorate ClO 1-3 ) ite (one fewer oxygen atoms than ate e.g. sulphite SO 2-3, chlorite ClO 1-2 ) hypo ite (1 oxygen atom e.g. hypochlorite ClO 1- ) Another wrinkle! When oxygen is combined with Group 1 metals, it can form a peroxide which has the formula X 2 O 2 rather than the expected X 2 O. These compounds are named the same as other ionic compounds except the ending is peroxide instead of oxide. 3

4 WRITING FORMULAS Having fun with nomenclature! Remember, for oxygen-containing polyatomic ions the name reflects the number of oxygen atoms present. Be sure to write the correct formula. Always check the back of the periodic table to be sure! sodium iodite sodium periodate potassium sulphide potassium sulphite potassium bisulphate potassium thiosulphate magnesium nitride NAMING calcium bromite calcium perbromate lithium phosphide lithium dihydrogen phosphate ammonium nitrate ammonium thiosulphate magnesium nitrite COMPOUNDS CONTAINING POLYATOMIC IONS Ba(OH) 2 HCN Ca(OH) 2 Al(CN) 3 RbOH NaSCN Na 2 O 2 KSCN NaHCO 3 NH 4 SCN KHCO 3 Ca(SCN) 2 KBr NaCl KBrO 2 NaClO Na 2 SO 3 NaClO 3 Na 2 SO 4 LiI NaHSO 3 LiIO K 3 P LiIO 3 K 3 PO 4 CaSO 3 K 2 HPO 4 Ca(HSO 4 ) 2 KH 2 PO 4 Na 3 N NaNO 3 NaNO 2 WRITING FORMULAS COMPOUNDS CONTAINING POLYATOMIC IONS & TRANSITION METALS copper (II) sulphate iron (II) chlorate cobalt (II) carbonate gold (III) acetate antimony (III) thiosulphate tin (II) hydroxide copper (I) acetate antimony (V) acetate iron (III) cyanide copper (II) permanganate lead (II) carbonate lead (II) bicarbonate lead (IV) thiocyanate copper (I) peroxide iron (III) hypochlorite lead (IV) carbonate manganese (II) oxalate gold (III) acetate mercury (I) nitrate iron (III) dichromate tin (IV) oxalate lead (IV) hydroxide gold (III) chromate gold (III) chloride lead (IV) bicarbonate copper (II) peroxide lead (II) hypochlorite copper (II) sulphite ammonium hypochlorite manganese (II) chlorate 4

5 MIXED IONIC COMPOUNDS WITH POLYATOMIC IONS AND MULTI-VALENT METALS Name of compound 1. rubidium selenide 2. aluminum chloride 3. gold (I) sulphate 4. nickel (II) thiocyanate 5. gold (III) chloride 6. potassium hydrogen sulphate 7. chromium (III) sulphate 8. lead (IV) carbonate 9. gold (III) acetate 10. manganese (III) phosphate 11. barium bromide 12. iron (III) chlorate 13. manganese (II) oxalate 14. sodium iodate 15. lead (IV) hydroxide Formula of compound 16. CaO 17. Mn 3 P Ca(SCN) ZnS 20. Hg 2 O 21. SnF Zn 2 Si 23. Ag 2 S 24. KCN 25. Cu 2 S 26. FeS 27. Sr(CN) KBr 29. Pb 3 N K 2 HPO 3 NAMING- BINARY ACIDS: hydrogen ide becomes hydro ic acid (aq) hydrogen ate becomes ic acid (aq) hydrogen ite becomes ous acid (aq) Complete the following table. These are the binary acids that you should become familiar with. Important information...essentially any hydrogen containing binary compound or molecule, WHEN DISSOLVED IN WATER is a binary acid. Notice that I have made WHEN DISSOLVED IN WATER stand out. I did this because it is important and will prevent unnecessary confusion. 5

6 Formula Name of Binary Compound Name of Acid (aq) HF hydrogen fluoride hydrofluoric acid HCl HBr HI H 2 S H 2 Se Complete the following table. Formula Name of Compound Name of Acid (Aqueous Solution) HMnO 4 hydrogen permanganate permanganic acid HNO 3 HNO 2 H 2 CO 3 H 2 SO 4 H 2 SO 3 H 3 PO 4 HClO 4 HClO 3 HClO 2 HClO **** YOU RE ALMOST DONE!!!! ***** LAST ONE! MOLECULAR COMPOUNDS (BETWEEN NON-METAL AND NON-METAL) WRITING FORMULAS When given PREFIX SYSTEM names The names in the exercise that follows were written using prefixes mono-, di-, tri-, etc. The prefix system was used to write the name for the molecules that follow. Notice that mono- is not normally added to the first part of the name although its meaning is implied. Some molecular compounds have traditional names that are more commonly used (e.g. dicarbon pentahydridehydroxide is C 2 H 5 OH (l) and is also known as ethanol or grain alcohol). Thus you will have to memorise certain important covalent formulae and names for this course. nitrogen dioxide PI 3 silicon dioxide As 2 S 5 ozone N 2 O methane CO 2 sulphur trioxide CCl 4 carbon monoxide C 3 H 8 arsenic trichloride PO 5 phosphorous pentasulphide C 6 H 12 O 6 arsenic pentachloride P 2 S 5 diphosphorous pentoxide S 2 O 5 dinitrogen tetroxide SO 3 6