Nomenclature:
Naming Chemicals
PO43phosphate ion
HC2H3O2
Acetic Acid
C2H3O2acetate ion
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Before naming…. — Some things you MUST know to be successful…. You really need to commit these things to memory 1
Ions: A Refresher — 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-­‐ electrostatic attractions. — Ionic solids are called salts. — Salts are electrolytes; they conduct electricity when dissolved in water (aq.) ž Conductors
of heat and electricity
ž Make cations (lose e to become + charged)
ž Malleable (made into sheets)
ž Ductile (made into wire)
-
2
ž  Are
a brittle solid or a gas
ž  Make anions (gain e- to become - charged)
ž  Covalently bond to each
other
• Characteristics of both
metals and nonmetals
• More metallic as you go
down PT
3
+1
Common Ions of Elements
+3
+2
+/-
4 -3 -2 -1 0
Variable, always +
Predicting Charges on Monatomic Ions
KNOW THESE !!!!
+1 +2
-3 -2 -1
0
Cd+2
4
Polyatomic Ions —  Groups of covalently bonded atoms that have a charge. * NO3-­‐ :nitrate ion * NO2-­‐ :nitrite ion —  Yes, you have to memorize them. —  Listed in your resource handbook: memorize the required list!!!! Pa9erns for Polyatomic Ions — -­‐ate ion —  chlorate = ClO3-­‐ — -­‐ate ion plus 1 O ⇒ same charge, per-­‐ prefix —  perchlorate = ClO4-­‐ — -­‐ate ion minus 1 O ⇒ same charge, -­‐ite suffix —  chlorite = ClO2-­‐ — -­‐ate ion minus 2 O ⇒ same charge, hypo-­‐ prefix, -­‐ite suffix —  hypochlorite = ClO-­‐ 5
Polyatomic Ions You can make additional polyatomic ions by adding a H+
to the ion!
—  CO3 -2 is carbonate:
–
—  HCO3 is hydrogen carbonate
—  PO43- is phosphate:
—  HPO4
2-
is hydrogen phosphate
–
—  H2PO4 is dihydrogen phosphate
2-
—  SO4 is sulfate
–
—  HSO4 is hydrogen sulfate
The 3 types of Chemical Bonds:
Metallic, Ionic and Covalent
—  Electronegativity and Bond Type —  Bond type can be determined by the difference in electronegativty 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 6
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
Ionic Bonds —  Complete transfer of 1 or more
electrons from one atom to another
(or a polyatomic ion)
—  one loses one or more e-, the other
gains those e-s
—  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 7
Ionic compounds are neutral — 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 COMPOUNDS
FORMED FROM
IONS CATION +
ANION --->
COMPOUND
Na+ + Cl-­‐ -­‐-­‐> NaCl A neutral compound
requires
equal number of +
and - charges.
8
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 (as you already know) —  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. —  For more on this, go back to bonding 9
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…some general help for naming: —  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! 10
Naming ionic compounds: — Remember that those are compounds that have a metal first in the formula*, and then a nonmetal or a polyatomic ion. — We can handle these as simple types —  binary (2 elements) compounds —  Ternary(more than 2 element) compounds — Names are always for the smallest whole number ratio of the elements, the formula unit *Two exceptions to this rule: —  Compounds that start with either ammoniums (NH4+) or hydronium (H3O+)
General informaHon 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 11
Example: CaCl2, or calcium chloride
ž  Name
the cation first, then the anion root
with an –ide suffix
ž  For
CaCl2, the monatomic cation is Ca2+ ,
calcium, and the monatomic anion is Cl- ,
named chloride.
ž
We use chloride because the root for
chlorine is chlor, and we use = root + -ide
for the second element in binary
compounds
ž  CaCl2 = calcium chloride
Learning Check Complete the names of the following binary compounds: Na3N
KBr
Al2O3
MgS
12
If the Metal is a TransiHon 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+, Cu2+ Fe2+, Fe3+ copper(I) ion iron(II) ion copper (II) ion iron(III) ion Type II CaHons 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. FeCl3
(Fe3+) iron (III) chloride
CuCl
copper (I) chloride 4+
SnF4 (Sn )
tin (IV) fluoride 2+
PbCl2 (Pb )
lead (II) chloride Fe2S3
(Fe3+) iron (III) sulfide (Cu+ ) You will appreciate this more when we go from names to formulas! 13
Type II CaHons 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 CaHons formed from TransiHon Metals (you do not have to memorize these) 14
Learning Check Complete the names of the following binary compounds with variable metal ions: FeBr2
CuCl
SnBr4
Fe2O3
Hg2S
General naming rules for covalent (molecular) compounds — Names are two words, with prefixes. —  Prefixes tell you how many. — Use the first element’s whole name with the appropriate prefix —  *********except mono. —  NEVER use mono for the first element — For the second element, use the root of the name and the -­‐ide ending with appropriate prefix for that many. 15
Covalent Naming Prefixes: PREFIX mono-­‐ di-­‐ tri-­‐ tetra-­‐ penta-­‐ hexa-­‐ hepta-­‐ octa-­‐ nona-­‐ deca-­‐ NUMBER 1 2 3 4 5 6 7 8 9 10 Example: CO2 is carbon dioxide
ž  Name
the first element, using a prefix if
there is more than one atom of the element
present
ž  Name
the second element, using the
appropriate prefix in all cases
ž
CO2 is carbon dioxide because there is one
carbon (no prefix when there is only one
atom of the element,) and two oxygens (diprefix)
16
Learning Check 1. P2O5 a) phosphorus oxide b) phosphorus pentoxide c) diphosphorus pentoxide 2. Cl2O7
a) dichlorine heptoxide b) dichlorine oxide c) chlorine heptoxide 3. Cl2 a) chlorine
b) dichlorine c) dichloride Learning Check Give the names of following covalent compounds: CO CO2 PCl3 CCl4 N2O 17
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: —  H2O
water, not dihydrogen monoxide —  NH3 ammonia, not nitrogen trihydride Hydrates: Ionic Compounds·∙Water — Some salts trap water crystals when they form crystals. —  Ex: CuSO4·∙H2O — 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. — CuSO4·∙H2O is copper (II) sulfate pentahydrate 18
Hydrates — In the formula you put a dot and then write the number of molecules. — Calcium chloride dihydrate = CaCl2•2Η2Ο
— Chromium (III) nitrate hexahydrate = Cr(NO3)3• 6H2O 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: —  Non-­‐oxyacids —  Oxyacids 19
Naming acids: Non-­‐Oxy acids If the acid doesn’t have oxygen — add the prefix “hydro-­‐” — change the suffix “–ide” to “-­‐ic acid” HCl H2S HCN Hydrochloric acid Hydrosulfic acid Hydrocyanic acid Naming acids: Oxy 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! H2CrO4 HMnO4 HNO2 Chromic acid Manganic acid Nitrous acid 20
Acid Nomenclature Flowchart ACIDS
start with 'H'
2 elements
3 elements
hydro- prefix
-ic ending
no hydro- prefix
-ate ending
becomes
-ic ending
Anion
Ending
Binary à
Ternary
-ite ending
becomes
-ous ending
Acid Name
-ide
hydro-(stem)-ic acid
-ate
(stem)-ic acid
-ite
(stem)-ous acid
An easy way to remember which goes with which…
“In the cafeteria, you ATE something ICky”
21
Acid Nomenclature §  HBr (aq)
§  H2CO3 (aq)
§  H2SO3 (aq)
Acid
Name
HNO3
HNO2
H2SO4
H2SO3
H3PO4
HC2H3O2
22
Name ‘Em! — HI (aq) — HCl (aq) — H2SO3 (aq) — HNO3 (aq) — HIO4 (aq) WriHng 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 + fluoride ion 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. 23
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: NaF2 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. WriHng the formula… Write the formula for the barium chloride, the compound that will form between Ba2+ and Cl-­‐. Solution: 1. Write the cation, and then the anion 2. Balance charge with the number of + and – ions Ba++
ClThink:
Cl
Why is Cl- written twice?
3. Write the number of ions needed as subscripts: BaCl2
24
So what if the oxidaHon 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. Is there an easier way? —  Yes. The “Criss Cross” method. You take the charge number from the cation, and you make it the number of anions (subscript)and take the charge on the anion, and you make that many cations (subscript). Criss-­‐Crossing in acHon: Example: Lead (II) nitrate Pb2+ N3-­‐
2+
Pb N3-­‐ *the charges do not balance Pb3N2 —  The 2 and the 3 are brought down to the opposite element, so that there are now 3 Pb2+ ions and 2 N3-­‐ ions —  This means there were 6e-­‐ transferred from the lead atoms to the nitrogen atoms; the compound is neutral 25
Learning Check Write the correct formula for the compounds containing the following ions: 1. Na+ and S2-­‐ a) NaS b) Na2S c) NaS2 2. Al3+ and Cl-­‐ a) AlCl3 b) AlCl c) Al3Cl 3. Mg2+ and N3-­‐ a) MgN b) Mg2N3
c) Mg3N2 Ternary Ionic Compounds: — Contain at least 3 elements — There MUST be at least one polyatomic ion (it helps to circle the ions) Examples: NaNO3 Sodium nitrate K2SO4 Al(HCO3)3
Potassium sulfate Aluminum bicarbonate (Aluminum hydrogen carbonate) 26
Specifics for ternary ionic compounds Examples: NaNO3, and Co(NO3)2
—  Name the cation first, then polyatomic ion —  For NaNO3, the monatomic cation is Na+ , sodium, and the polyatomic anion is NO3- , named nitrate. —  NaNO3 is sodium nitrate —  For Co(NO3)2, the monatomic cation is Co+2, cobalt (II) and the polyatomic anion is NO3- , named nitrate. —  Co(NO3)2 is cobalt (II) nitrate Learning Check Match each set with the correct name: 1. Na2CO3
a) magnesium sulfite MgSO3
b) magnesium sulfate MgSO4
c) sodium carbonate 2 .
Ca(HCO3)2 a) calcium carbonate CaCO3
b) calcium phosphate Ca3(PO4)2 c) calcium bicarbonate 27
WriHng Formulas for Ternary Ionic Compounds —  Write the cation first, then the anion. —  Overall charge must equal zero. —  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. WriHng Formulas, cont’d Example: Cr2+ PO43-­‐
*
the charges do not balance Cr2+ PO43-­‐ Cr3(PO4)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! 28
Learning Check 1. aluminum nitrate a) AlNO3 b) Al(NO)3 c) Al(NO3)3 2. copper(II) nitrate a) CuNO3
b) Cu(NO3)2
c) Cu2(NO3)
3. Iron (III) hydroxide a) FeOH
b) Fe3OH 4. Tin(IV) hydroxide a) Sn(OH)4 b) Sn(OH)2 c) Fe(OH)3 c) Sn4(OH) Ternary Ionic Nomenclature: You Criss-­‐cross these, too. Sodium Sulfate Iron (III) hydroxide Ammonium carbonate 29
Write the Formula: Copper (II) chlorate Calcium nitride
Aluminum carbonate
Potassium bromide Barium fluoride
Cesium hydroxide NEVER You criss-­‐cross charges with covalent compounds. never Since you are sharing electrons, rather than giving them away/ picking them up, the charges are not relevant. 30
More Covalent Examples §  arsenic trichloride
§  dinitrogen pentoxide
§  tetraphosphorus decoxide
Formulas for acids — Backwards from names. — If it has hydro-­‐ in the name it has no oxygen — Anion ends in “-­‐ide” — No hydro, anion ends in “-­‐ate or –ite” — Write anion and add enough H’s to balance the charges. 31
Acid Nomenclature §  hydrofluoric acid
§  sulfuric acid
§  nitrous acid
Formulas for acids hydrofluoric acid dichromic acid carbonic acid hydrophosphoric acid hypofluorous acid perchloric acid phosphorous acid 32
Write the Formula! —  Hydrobromic acid —  Nitrous acid —  Carbonic acid —  Phosphoric acid —  Hydrotelluric acid Mixed PracHce 1.
2.
3.
4.
5.
6.
7.
8.
9.
Dinitrogen monoxide Potassium sulfide Copper (II) nitrate Dichlorine heptoxide Chromium (III) sulfate Iron (III) sulfite Calcium oxide Barium carbonate Iodine monochloride 33
—  Match each set with the correct name: Na2CO3
MgSO3
MgSO4
Ca(HCO3)2
CaCO3
Ca3(PO4)2 a) sodium carbonate b) magnesium sulfite c) magnesium sulfate a) calcium bicarbonate b) calcium carbonate c) calcium phosphate Mixed PracHce! Name the following: 1.  Na2O 2.  CaCO3 3.  PbS2
4.  Sn3N2 5.  Cu3PO4 6.  HgF2 34
Mixed Review Name the following compounds: 1. CaO 2. 3. a) calcium oxide c) calcium (II) oxide
b) calcium(I) oxide d) calcium monoxide SnCl4 a) tin tetrachloride b) tin(II) chloride c) tin(IV) chloride N2O3 a) nitrogen oxide c) nitrogen trioxide
b) dinitrogen trioxide Mixed PracHce 1.  BaI2 2.  P4S3 3.  Ca(OH)2 4.  FeCO3 5.  Na2Cr2O7 6.  I2O5 7.  Cu(ClO4)2 8.  CS2 9.  B2Cl4 35
DONE! Now it is Hme to study! 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 H2O would be H[2]O And Al2(SO4)3 would be Al[2](SO[4])[3] Additional Polyatomic Ions (you do not have to memorize these, but they are in the game!) Borate = BO3 -­‐3 ; Silicate = SiO4 -­‐4 ; Manganate = MnO4 -­‐2 (permanganate is -­‐1) 36