Presentation on theme: "Nomenclature : Naming Chemicals PO 4 3- phosphate ion C 2 H 3 O 2 - acetate ion HC 2 H 3 O 2 Acetic Acid."— Presentation transcript:
Nomenclature : Naming Chemicals PO 4 3- phosphate ion C 2 H 3 O 2 - acetate ion HC 2 H 3 O 2 Acetic Acid
Before naming…. Some things you MUST know to be successful…. You really need to commit these things to memory
Ions Atoms or groups of atoms with a charge. Cations- positive ions - get by losing electron(s). Anions- negative ions - get by gaining electron(s). Ionic bonding- held together by the opposite charges. (usually a metal and a nonmetal) Ionic solids are called salts. Salts are electrolytes; they conduct electricity when dissolved in water (aq.)
Conductors of heat and electricity Make cations (lose e - to become + charged) Malleable (made into sheets) Ductile (made into wire)
Are a brittle solid or a gas Make anions (gain e - to become - charged) Covalently bond to each other
Characteristics of both metals and nonmetals More metallic as you go down PT
+1 +2-2-3 +/- 4 +3+3 Variable, always + Common Ions of Elements
Predicting Charges on Monatomic Ions KNOW THESE !!!! +1 +2 -3 -2 -1 0 Cd +2
Polyatomic Ions Groups of covalently bonded atoms that have a charge. * NO 3 - :nitrate ion * NO 2 - :nitrite ion Yes, you have to memorize them. Listed in your resource handbook: memorize the required list!!!!
Patterns for Polyatomic Ions -ate ion chlorate = ClO 3 - -ate ion plus 1 O same charge, per- prefix perchlorate = ClO 4 - -ate ion minus 1 O same charge, -ite suffix chlorite = ClO 2 - -ate ion minus 2 O same charge, hypo- prefix, -ite suffix hypochlorite = ClO -
Polyatomic Ions You can make additional polyatomic ions by adding a H + to the ion! CO 3 -2 is carbonate HCO 3 – is hydrogen carbonate PO 4 3- is phosphate HPO 4 is hydrogen phosphate H 2 PO 4 is dihydrogen phosphate HSO 4 –2 is hydrogen sulfate
The 3 types of Chemical Bonds: Ionic, Covalent, & Metallic Electronegativity and Bond type Bond type can be determined by the difference in electronegativity between the bonds involved. Differences of: ≥ 2 = ionic 0.5 – 1.9 = polar covalent ≤ 0.4 = nonpolar covalent Metals bonded to other metals are metallically bonded, regardless of the difference in electronegativity.
Metallic bonds The atoms of metals are held together when the atom’s valence electrons float around the nuclei of the metals – the “sea of electrons” Electrostatic forces keep everything together
The 3 types of Chemical Bonds: Ionic, Covalent, & Metallic Ionic—complete transfer of 1 or more electron from one atom to another (or another group) one loses one or more e -, the other gains those e - Atoms involved are a metal and either a non-metal or a polyatomic ion The cation and anion are attracted to each other by electrostatic attraction.
Ionic compounds are neutral That is, they have no overall charge This is because the number of electrons that are given up by the metal is the same number of electrons that are gained by the anion for the formula. Formulas reflect this neutrality- the charges on the individual ions are not written in because they cancel out overall for the compound
CATION + ANION ---> COMPOUND COMPOUND CATION + ANION ---> COMPOUND COMPOUND A neutral compound requires equal number of + equal number of + and - charges. A neutral compound requires equal number of + equal number of + and - charges. COMPOUNDS FORMED FROM IONS Na + + Cl - --> NaCl
Covalent Bonds 2, 4, or 6 valence electrons that are shared between atoms We are going to name only simple covalent compounds that have 2 elements involved
Most bonds are somewhere in between ionic and covalent Because not all atoms share e - equally The conventions of naming assume absolute difference in bond types Metals bonded to nonmetals or polyatomic ions are classified as having ionic bonds* Materials made out of all non-metals are classified as having covalent bonds* * semimetals are not a classification in naming; you need to treat the elements that are on the right of the line as non-metals, and those on the left as metals. More on this when we talk about bonding
Naming things: If there is only one element present, name it. Atomic substances do not require “special” naming. For anything with more than one element, remember that there is ONE MAIN THING to look for: Is there a metal first?
So… Look to see if there is a metal first in the formula Again, semimetals are not a classification in naming; you need to treat the elements that are on the right of the line as non-metals, and those on the left as metals. If there are only metals, name both metals (metallic bonding; nothing else need be done) If ONLY the first element is a metal, then the compound is an ionic compound Nonmetals only signify a covalent compound There is a flow chart in your handbook to help!
Naming ionic compounds: Remember that those are compounds that have a metal first in the formula*, and then a nonmetal or a polyatomic ion. *Two exceptions to this rule: Compounds that start with either ammoniums (NH 4 + ) or hydronium (H 3 O + ) We can handle these as simple binary (2 element) and ternary (more than two element) compounds
General information for naming ionic compounds If the cation is monatomic- Name the metal (cation). Use Roman Numerals for transition metals (ONLY) after the metal If the cation is polyatomic- name it. If the anion is monatomic- name it but change the ending to –ide. If the anion is poly atomic- just name it Practice.
Name the cation first, then the anion root with an –ide suffix For CaCl 2, the monatomic cation is Ca 2+, calcium, and the monatomic anion is Cl , named chloride. We use chloride because the root for chlorine is chlor, and we use = root + -ide for the second element in binary compounds CaCl 2 = calcium chloride Example: CaCl 2, or calcium chloride
Practice Naming Binary Ionic Compounds Examples: NaCl ZnI 2 Al 2 O 3
Learning Check Complete the names of the following binary compounds: Na 3 N KBr Al 2 O 3 MgS
If the Metal is a Transition Metal… Transition metals are Type II Cations, and are elements that can have more than one possible charge. They MUST have a Roman Numeral to indicate the charge on the individual ion. 1+ or 2+ 2+ or 3+ Cu +, Cu 2+ Fe 2+, Fe 3+ copper(I) ion iron(II) ion copper (II) ion iron(III) ion
Type II Cations These elements REQUIRE Roman Numerals because they can have more than one possible charge: anything except Group 1A, 2A, Ag, Zn, Cd, and Al (You should already know the charges on these!) Or another way to say it is: Transition metals and the metals in groups 4A and 5A (except Ag, Zn, Cd, and Al) require a Roman Numeral. FeCl 3 (Fe 3+ ) iron (III) chloride CuCl (Cu + ) copper (I) chloride SnF 4 (Sn 4+ ) tin (IV) fluoride PbCl 2 (Pb 2+ )lead (II) chloride Fe 2 S 3 (Fe 3+ )iron (III) sulfide You will appreciate this more when we go from names to formulas!
Type II Cations Some Type II cations have a name using the “old” system as well as the “new system”. The old system, still widely used, adds to the root or stem of the Latin name of the metal the suffixes –ous and –ic. These represent the lower and higher charges respectively.
Examples of Older Names of Cations formed from Transition Metals (you do not have to memorize these)
Learning Check Complete the names of the following binary compounds with variable metal ions: FeBr 2 CuCl SnBr 4 Fe 2 O 3 Hg 2 S
Writing Formulas for Ionic Compounds from Names Formulas of ionic compounds are determined from the charges on the ions Na + F Na + + F - NaF Sodium atom + fluorine atom sodium fluoride Charge balance: 1+ + 1- = 0 Remember that all ionic compounds have no net charge, and that the charges are not written in! Ever. Nope.
Neutral, you say? Formulas are written to make the compound have a neutral charge overall. You do NOT write the charges in the formula because they MUST cross out to accurately represent the compound. Ex: NaF 2 is INCORRECT for sodium chloride because Na has an oxidation state of +1, and F of -1. There is a one to one ratio of Na + to F - to make a neutral ionic compound.
Writing the formula… Write the formula for the barium chloride, the compound that will form between Ba 2+ and Cl -. Solution: 1. Write the cation, and then the anion 2. Balance charge with the number of + and – ions 3. Write the number of ions needed as subscripts: Ba++ Cl-Think: Cl-Why is Cl written twice? BaCl2
So what if the oxidation numbers aren’t even? If the oxidation numbers or charges do not balance, you can write the number of ions of each until you get the same number of each charge in total. Yes. The “Criss Cross” method. You take the charge number from the cation, and you make it the number of anions, and take the charge on the anion, and you make that many cations. Is there an easier way?
Criss-Crossing in action: Example: Lead (II) nitrate Pb 2+ N 3- *the charges do not balance Pb 2+ N 3- Pb 3 N 2 The 2 and the 3 are brought down to the opposite element, so that there are now 3 Pb 2+ ions and 2 N 3- ions This means there were 6e - transferred from the lead atoms to the nitrogen atoms; the compound is neutral
Learning Check Write the correct formula for the compounds containing the following ions: 1. Na + and S 2- a) NaS b) Na 2 Sc) NaS 2 2. Al 3+ and Cl - a) AlCl 3 b) AlCl c) Al 3 Cl 3. Mg 2+ and N 3- a) MgN b) Mg 2 N 3 c) Mg 3 N 2
Ternary Ionic Compounds: Contain at least 3 elements There MUST be at least one polyatomic ion (it helps to circle the ions) Examples: NaNO 3 Sodium nitrate K 2 SO 4 Potassium sulfate Al(HCO 3 ) 3 Aluminum bicarbonate (Aluminum hydrogen carbonate)
Name the cation first, then polyatomic ion For NaNO 3, the monatomic cation is Na +, sodium, and the polyatomic anion is NO 3 , named nitrate. NaNO 3 is sodium nitrate For Co(NO 3 ) 2, the monatomic cation is Co +2, cobalt (II) and the polyatomic anion is NO 3 , named nitrate. Co(NO 3 ) 2 is cobalt (II) nitrate Examples: Examples: NaNO 3, and Co(NO 3 ) 2
Learning Check Match each set with the correct name: 1. Na 2 CO 3 a) magnesium sulfite MgSO 3 b) magnesium sulfate MgSO 4 c) sodium carbonate 2.Ca(HCO 3 ) 2 a) calcium carbonate CaCO 3 b) calcium phosphate Ca 3 (PO 4 ) 2 c) calcium bicarbonate
Writing Formulas for Ternary Ionic Compounds Write the cation first, then the anion. Overall charge must equal zero. Overall charge must equal zero. If charges cancel If charges cancel, just write symbols. If not, use subscripts to balance charges. Use parentheses to show more than one of a particular polyatomic ion. Use Roman numerals indicate the ion’s charge when needed (transition metals) Remember that the final formula should not have charges written in.
Writing Formulas with Polyatomic Ions Example: Cr 2+ PO 4 3-* the charges do not balance Cr 2+ PO 4 3- Cr 3 (PO 4 ) 2 The polyatomic ions is in parentheses whenever a subscript is added This is so that we know to count a number of those groups!
Learning Check 1. aluminum nitrate a) AlNO 3 b) Al(NO) 3 c) Al(NO 3 ) 3 2. copper(II) nitrate a) CuNO 3 b) Cu(NO 3 ) 2 c) Cu 2 (NO 3 ) 3. Iron (III) hydroxide a) FeOHb) Fe 3 OHc) Fe(OH) 3 4. Tin(IV) hydroxide a) Sn(OH) 4 b) Sn(OH) 2 c) Sn 4 (OH)
Ternary Ionic Nomenclature: You Criss-cross these, too. Sodium Sulfate Iron (III) hydroxide Ammonium carbonate
Ternary Ionic Nomenclature: You Criss-cross these, too. Sodium Sulfate Na + and SO 4 -2 Na 2 SO 4 Iron (III) hydroxide Fe +3 and OH - Fe(OH) 3 Ammonium carbonate NH 4 + and CO 3 –2 (NH 4 ) 2 CO 3
Write the Formula: Copper (II) chlorate Calcium nitride Aluminum carbonate Potassium bromide Barium fluoride Cesium hydroxide
General naming rules for covalent compounds Names are two words, with prefixes. Prefixes tell you how many. First element whole name with the appropriate prefix, except mono. Second element, -ide ending with appropriate prefix. Practice
never You NEVER criss-cross charges with covalent compounds. Since you are sharing electrons, rather than giving them away/ picking them up, the charges are not relevant.
Name the first element, using a prefix if there is more than one atom of the element present Name the second element, using the appropriate prefix in all cases CO 2 is carbon dioxide because there is one carbon (no prefix when there is only one atom of the element,) and two oxygens (di- prefix) Example: Example: CO 2 is carbon dioxide
Learning Check 1.P 2 O 5 a) phosphorus oxide b) phosphorus pentoxide c) diphosphorus pentoxide 2.Cl 2 O 7 a) dichlorine heptoxide b) dichlorine oxide c) chlorine heptoxide 3. Cl 2 a) chlorine b) dichlorine c) dichloride
Learning Check Give the names of following covalent compounds: CO CO 2 PCl 3 CCl 4 N 2 O
CCl 4 N 2 O 5 SF 6 Covalent Naming Examples
Hydrates: Ionic Compounds·Water Some salts trap water crystals when they form crystals. Ex: CuSO 4 ·5H 2 O These are hydrates. Both the name and the formula needs to indicate how many water molecules are trapped. In the name we add the word hydrate with a prefix that tells us how many water molecules. CuSO 4 ·5H 2 O is copper (II) sulfate pentahydrate
Hydrates In the formula you put a dot and then write the number of molecules. Calcium chloride dihydrate = CaCl 2 2 Chromium (III) nitrate hexahydrate = Cr(NO 3 ) 3 6H 2 O
Acid Nomenclature Acids Compounds that form H + in water. Formulas usually begin with ‘H’. In order to be an acid instead of a gaseous covalent compound, it must be aqueous Meaning dissolved in water; symbolized by (aq) Ternary acids are ALL aqueous Two types: Oxyacids Non-oxyacids
Naming acids If the acid doesn’t have oxygen add the prefix hydro- change the suffix -ide to -ic acid HClHydrochloric acid H 2 SHydrosulfic acid HCNHydrocyanic acid
Naming acids If the formula has oxygen in it write the name of the anion, but change ate to -ic acid ite to -ous acid Watch out for sulfuric and sulfurous! H 2 CrO 4 HMnO 4 HNO 2 Chromic acid Manganic acid Nitrous acid
Write the Formula! Hydrobromic acid Boric acid Carbonic acid Phosphoric acid Hydrotelluric acid HBr (aq) H 3 BO 3(aq) H 2 CO 3(aq) H 3 PO 4(aq) H 2 Te (aq)
Common Names A lot of chemicals have common names as well as the proper IUPAC name. Chemicals that should always be named by common name and never named by the IUPAC method are: H 2 Owater, not dihydrogen monoxide NH 3 ammonia, not nitrogen trihydride
Match each set with the correct name: Na 2 CO 3 a) sodium carbonate MgSO 3 b) magnesium sulfite MgSO 4 c) magnesium sulfate Ca(HCO 3 ) 2 a) calcium bicarbonate CaCO 3 b) calcium carbonate Ca 3 (PO 4 ) 2 c) calcium phosphate
Mixed Review Name the following compounds: 1. CaO a) calcium oxideb) calcium(I) oxide c) calcium (II) oxided) calcium monoxide 2. SnCl 4 a) tin tetrachlorideb) tin(II) chloride c) tin(IV) chloride 3. N 2 O 3 a) nitrogen oxide b) dinitrogen trioxide c) nitrogen trioxide
Mixed Practice 1. BaI 2 2. P 4 S 3 3. Ca(OH) 2 4. FeCO 3 5. Na 2 Cr 2 O 7 6. I 2 O 5 7. Cu(ClO 4 ) 2 8. CS 2 9. B 2 Cl 4
Rainbow Matrix Game Link on Chemistry Geek.com on Chemistry I page http://chemistrygeek.com/rainbow Use [ ] to represent subscripts since you can’t enter subscripts into the computer So H 2 O would be HO And Al 2 (SO 4 ) 3 would be Al(SO) Additional Polyatomic Ions (you do not have to memorize these, but they are in the game!) Borate = BO 3 -3 ; Silicate = SiO 4 -4 ; Manganate = MnO 4 -2 (permanganate is -1)