Download presentation
Presentation is loading. Please wait.
1
Unit 0 Nomenclature: Naming Chemicals
PO43- phosphate ion HC2H3O2 Acetic Acid SAVE PAPER AND INK!!! When you print out the notes on PowerPoint, print "Handouts" instead of "Slides" in the print setup. Also, turn off the backgrounds (Design>Hide background graphics with all slides selected) C2H3O2- acetate ion
2
The Period Table identifies all elements by their atomic number, which can be read off the period table.
4
History of the Periodic Table
In 1869, Dmitri Mendeleev arranged the elements according to atomic mass in an attempt to classify them. He left spaces for elements that he predicted existed, yet hadn’t been discovered yet. This set him apart from others, and he was later proven correct.
5
Henry Moseley In 1913, Henry Moseley developed the concept of atomic numbers. He determined the frequencies of X-rays emitted as different elements were bombarded with high energy electrons. Each element produces X-rays of unique frequency, and the frequency increased as atomic mass increased.
6
Atomic Number Moseley arranged these frequencies in order by assigning a unique whole number, which he called the atomic number. He correctly identified the atomic number as the number of protons in the nucleus of the atom. This clarified some problems that Mendeleev had; Ar and K, Te and I.
7
Periodic Table Arrangement
Periods: Horizontal Rows (7) Indicates the energy level where the valence electrons are located. Example: An element in Period 4 has its valence electrons in the 4th energy level.
8
Periodic Table Arrangement
Groups/Families: Modern way of labeling vertical columns; numbered from 1-18 Representative Elements(main group): groups 1,2,13-18 Transition Elements: groups 3-12 located in the center
9
Periodic Table Arrangement
Groups/Families: Antiquated way of labeling vertical columns Roman numeral with letter A or B Representative Elements(main group): Group A elements Transition Elements: Group B elements
10
Group/Family Arrangement
Representative Elements(main group): groups 1,2,13-18 Form ions with only 1 charge Transition Elements: groups 3-12 located in the center Form ions with multiple charges
11
Groups 1 and 2 Group 1 – Alkali Metals Group 2 – Alkali Earth Metals
All solids 1 valence electron/form 1+ ions EXTREMELY reactive Reacts with water to form H2 gas and a base Group 2 – Alkali Earth Metals 2 valence electrons/form 2+ ions Reactive, but not as much as Group 1
12
Group 17 – Halogens 7 valence electrons
Most reactive of the non-metals! Gains electrons easily and forms (-) ions Reactivity increases down the group
13
Group 18 – Noble Gases Rare or inert gases 8 valence electrons
nonreactive gases (not found in compounds in nature) do not form ions
14
Groups 3 – 11 Transition Elements
Metallic characteristics Form ions with multiple charges Colored compounds
15
Broad Categories of the Periodic Table
16
Metals The elements on the left side of the table. Malleable/ Ductile
Lustrous Great Conductors of heat and electricity Form cations because they lose electrons Mostly solids, Hg is liquid
17
Metals Conductors of heat and electricity
Make cations (lose e- to become + charged) Malleable (made into sheets) Ductile (made into wire)
18
Non-Metals The elements on the right side of the table
Brittle as solids, with no luster Poor conductors of heat and electricity Form anions because they gain electrons They can be gases, liquids or solids
19
Nonmetals Are a brittle solid or a gas
Make anions (gain e- to become - charged) Covalently bond to each other
20
Semi-Metals (Metalloids)
Some properties are metallic, some are non-metallic and some are in-between They are found adjacent to the darkened stair case line with the exception of Al
21
Semi-metals (AKA Metalloids)
Characteristics of both metals and nonmetals More metallic as you go down PT
22
Chemical Formulas A molecular formula shows the exact number of atoms of each element in the smallest unit of a substance An empirical formula shows the simplest whole-number ratio of the atoms in a substance H2O molecular empirical H2O C6H12O6 CH2O O3 O N2H4 NH2
23
A diatomic molecule contains only two atoms
Covalent Bonding A molecule is two or more nonmetal atoms in a definite arrangement held together by chemical bonds that share electrons H2 H2O NH3 CH4 A diatomic molecule contains only two atoms H2, N2, O2, Br2, HCl, CO A polyatomic molecule contains more than two atoms O3, H2O, NH3, CH4
24
One way to remember these elements is:
Diatomic Molecules These seven elements occur naturally as molecules containing two atoms. One way to remember these elements is: Professor BrINClHOF © 2009, Prentice-Hall, Inc.
25
The ionic compound NaCl
Ionic Bonding A formula unit shows the smallest whole number ratio of ions in an ionic compound Ionic Bonding- metals and nonmetals are held together by the opposite charges- electrostatic attractions. Ionic solids are called salts . The ionic compound NaCl
26
Naming Ions and Ionic Compounds
Formulas for ionic compounds are generally empirical formulas. Ionic compounds are electronically neutral.
27
Ions: Atoms or groups of atoms with a charge.
Cations- positive ions - get by losing electron(s). Na1+ Anions- negative ions - get by gaining electron(s). Cl1- Monatomic ions-single atoms with a charge Al3+ Polyatomic ions – groups of atoms with a single charge ClO31-
28
Common Ions of Main Group Elements
+1 +3 +/-4 +2 -3 -2 -1 Variable, always +
29
Look at group B elements:
Most have more than 1 charge-do not need to memorize Silver, zinc and Cadmium only have 1 charge: must memorize them 2.5
30
Polyatomic Ions Groups of covalently bonded atoms that have a charge.
* NO3- :nitrate ion NO2- :nitrite ion MUST memorize their formula and charge-see module O NH41+ and Hg2 2+ are 2 positive polyatomics
31
Patterns 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- 14
32
Writing Formulas for Ionic Compounds from Names
Formulas of ionic compounds are determined from the charges on the ions Na S Na S2- Na2S Sodium ion + sulfide ion sodium sulfide Charge balance: = 0 Remember that all ionic compounds have no net charge, and that the charges are not written in!
33
Ionic Compounds are NEUTRAL!
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 fluoride 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. Correct answer is NaF
34
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 (subscript)and take the charge on the anion, and you make that many cations (subscript). Is there an easier way?
35
Criss-Crossing in action:
Example: Lead (II) nitride Pb2+ N3- *the charges do not balance Pb2+ N 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
36
Writing 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.
37
Writing Formulas, cont’d
Example: Cr2+ PO43- *the charges do not balance Cr2+ PO 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!
38
Examples: Write the following chemical formulas
Aluminum oxide Calcium bromide Sodium carbonate Al2O3 CaBr2 Na2CO3
39
Formula of Ionic Compounds
2 x +3 = +6 3 x -2 = -6 Al2O3 Al3+ O2- 1 x +2 = +2 2 x -1 = -2 CaBr2 Ca2+ Br- 1 x +2 = +2 1 x -2 = -2 Na2CO3 Na+ CO32-
40
Is there a metal first? 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?
41
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 notes to help!
42
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
43
Naming Ionic Compounds
Write the name of the cation. Use Roman Numerals for transition metals (ONLY) after the metal If the cation is polyatomic- name it. If the anion is an element, change its ending to -ide; if the anion is a polyatomic ion, simply write the name of the polyatomic ion. If the cation can have more than one possible charge, write the charge as a Roman numeral in parentheses. © 2009, Prentice-Hall, Inc.
44
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 or 3+ Cu+, Cu2+ Fe2+, Fe3+ copper(I) ion iron(II) ion copper (II) ion iron(III) ion
45
FeCl3 (Fe3+) iron (III) chloride
Type II Cations These elements REQUIRE Roman Numerals because they can have more than one possible charge: Transition metals and the metals in groups 4A and 5A (except Ag, Zn, Cd ) require a Roman Numeral. FeCl3 (Fe3+) iron (III) chloride CuCl (Cu+ ) copper (I) chloride SnF (Sn4+) tin (IV) fluoride PbCl (Pb2+) lead (II) chloride Fe2S (Fe3+) iron (III) sulfide
46
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.
47
Examples: Name the following ionic compounds
BaCl2 KNO3 K2O FeCl3 Mg(OH)2 SnO Barium chloride Potassium nitrate Potassium oxide Iron (III) chloride Magnesium hydroxide Tin (II) oxide
48
Examples of Older Names of Cations formed from Transition Metals (you do not have to memorize these)
49
Hydrates Some salts trap water crystals when they form crystals
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
50
Hydrates In the formula you put a dot and then write the number of molecules. Calcium chloride dihydrate = CaCl2·2H2O Chromium (III) nitrate hexahydrate = Cr(NO3)3· 6H2O
51
Naming Molecular Compounds
Greek prefixes are used to denote the number of atoms of each element present.
52
Naming Molecular Compounds
The prefix mono- is generally omitted for the first element. For ease of pronunciation, we usually eliminate the last letter of a prefix that ends in “o” or “a” when naming an oxide. Example: N2O5 is dinitrogen pentoxide not dinitrogen pentaoxide
53
Nomenclature of Binary Compounds
The ending on the more electronegative element is changed to -ide. CO2: carbon dioxide CCl4: carbon tetrachloride © 2009, Prentice-Hall, Inc.
54
Nomenclature of Binary Compounds
The less electronegative atom is usually listed first. A prefix is used to denote the number of atoms of each element in the compound (mono- is not used on the first element listed, however) . © 2009, Prentice-Hall, Inc.
55
Nomenclature of Binary Compounds
If the prefix ends with a or o and the name of the element begins with a vowel, the two successive vowels are often elided into one. N2O5: dinitrogen pentoxide © 2009, Prentice-Hall, Inc.
56
Examples: Name the following covalent compounds
HI NF3 SO2 N2Cl4 PCl5 Hydrogen monoiodide (hydrogen iodide) Nitrogen trifluoride Sulfur dioxide Dinitrogen tetrachloride Phosphorus pentachloride
57
Rules for Writing Formulas for Molecular Compounds
Using the first part of the name, translate the name of the element into a chemical symbol and then translate the prefix if there is one to its subscript. Using the second part of the name, translate the name of the element into a chemical symbol and then translate the prefix if there is one to its subscript. Dichlorine trioxide Cl2O3
58
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.
59
Acid Nomenclature Acids
Compounds that form H+ when dissolved 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) Two types: Binary Oxyacids
60
Acid Nomenclature Flowchart
61
Naming Binary Acids To name: 1) remove the –gen ending from hydrogen
change the –ide ending on the second element to –ic. Name the following acids HCl(aq) hydrogen chloride → hydrochloric acid H2S(aq) hydrogen sulfide → hydrosulfuric acid
62
Naming acids: Non-Oxy acids
If the acid doesn’t have oxygen add the prefix “hydro-” change the suffix “–ide” to “-ic acid” HCl Hydrochloric acid H2S Hydrosulfic acid HCN Hydrocyanic acid
63
Naming Ternary 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! HNO3 H2SO4 H2CO3 H3PO3 nitric acid sulfuric acid carbonic acid phosphorous acid
64
Acid Nomenclature HBr (aq) Binary Acid H2CO3 (aq) Oxyacid
2 elements, -ide H2CO3 (aq) Oxyacid 3 elements, -ate H2CO2 (aq) Oxyacid 3 elements, -ite hydrobromic acid carbonic acid carbonous acid
66
Writing Formulas for acids
Backwards from names. If it has hydro- in the name it has no oxygen: Binary Acid Anion ends in “-ide” No hydro, : Ternary Acid anion ends in “-ate or –ite” Write anion and add enough H’s to balance the charges.
67
A base can be defined as a substance that forms
hydroxide ions (OH-) when dissolved in water. Most bases are metal hydroxides or NH3 (Ammonia) There are also organic bases. NaOH sodium hydroxide KOH potassium hydroxide Ba(OH)2 barium hydroxide
68
Name the following bases
Remember, these are just ternary ionic compounds! Sr(OH)2 Fe(OH)3 Strontium hydroxide Iron(III) hydroxide
69
BaI2 P4S3 Ca(OH)2 CoCO3 Na2Cr2O7 I2O5 Zn(ClO4)2 CS2 B2Cl4
Mixed Practice: Decide whether each compound is an Ionic Compound, Molecular Compound, Acid, or Base and write its name BaI2 P4S3 Ca(OH)2 CoCO3 Na2Cr2O7 I2O5 Zn(ClO4)2 CS2 B2Cl4
70
Chromium (III) sulfate Ferric sulfite Calcium oxide Barium carbonate
Mixed Practice: Decide whether each compound is an Ionic Compound, Molecular Compound, Acid, or Base and write its formula Dinitrogen monoxide Potassium sulfide Copper (II) nitrate Dichlorine heptoxide Chromium (III) sulfate Ferric sulfite Calcium oxide Barium carbonate Iodine monochloride
71
Organic Compounds Compounds containing carbon
Can contain elements such as hydrogen, nitrogen, sulfur, phosphorus, oxygen & the halogens Have relatively low melting points, low boiling points poor conductivity, good solubility in other organic solvents
72
A chemical formula denotes the composition of the substance.
A molecular formula shows the exact number of atoms of each element in a molecule. C4H10 A structural formula shows not only the elemental composition, but also the general arrangements. A condensed structural formula is a shorthand representation that leaves the bond lines out but indicates what is bonded to each carbon or other atoms
73
Hydrocarbons Hydrocarbons contain only carbon and hydrogen.
Prefixes used in naming: 1- meth 2-eth 3-prop 4-but pent hex hept 8- oct non dec The simplest hydrocarbons are called alkanes. (CnH2n+2) Saturated hydrocarbon chain-connected by ONLY single bonds Tetrahedral geometry-sp3 hybridization Least reactive of hydrocarbons Can be in continuous chain or rings Can have substituent groups attached to chain
74
Organic Compounds
75
Organic Compounds
76
How to Name Straight Chain Alkanes
Count the number of carbons in the chain. Use the prefix stem to represent the number of carbons Use the suffix –ane CH4 CH3CH2CH3
77
How to Name Branched Chain Alkanes
Identify & name the longest, continuous carbon chain. This is called the parent chain which is named using a root to indicate the # of carbons followed by “ane”. Identify & name the substituent groups located off the continuous chain: Alkyl groups are named using a root to indicate the # of carbons in the group followed by “yl”. Examples -CH3 is methyl -CH2CH3 is ethyl CH2CH2CH3 is propyl Halogen groups are name like this F: fluoro -Cl: chloro (The prefixes di-, tri-,etc are used to indicate multiple identical substituents.) 3. The position of the substituent groups are specified by numbering the longest chain starting at the end closest to the branching (the substituent group).
78
How to Name Branched Chain Alkanes
4. Designate the location of each substituent group by an appropriate number & name. Identify where in the chain the substituent group is located with a number placed before the name. If two are on the same carbon use that number twice. Separate the number and the name with a hyphen and commas to separate numbers from each other. 5. The location & name of the substituent groups are followed by the root alkane name. The substituents are listed in alpha order. Prefixes are not considered when alphabetizing.
79
Examples CH3CH(CH3)CH2CH3
80
Alkenes Hydrocarbons can also be alkenes. (CnH2n)
Unsaturated hydrocarbon chain-carbons are connected by AT LEAST 1 double bond Trigonal Planar geometry-sp2 hybridization Can have substituent groups attached to chain
81
How to Name Alkenes 1. Indicate where the double bond is by numbering the longest chain that contains both the carbons of the double bond starting with the one closest to the bond. The smaller number of the two carbon atoms of the double bond is used as the double bond locator. 2. Then use the prefix stem to indicate the number of carbon atoms in the chain & the suffix “ene” ending. 3. Follow rules from “alkanes” to name substituent groups attached to alkenes. If the double bond is in the center of the chain, the nearest substituent group rule is used to determine where numbering begins If more than 1 double bond is present, the compound is named diene, triene, etc. Each double bond is given a locator number.
82
Alkene Examples C3H6
83
Alkynes Hydrocarbons can also be alkynes. (CnH2n-2)
Unsaturated hydrocarbon chain-carbons are connected by AT LEAST 1 triple bond Linear geometry-sp hybridization Can have substituent groups attached to chain
84
How to Name Alkynes 1. Indicate where the triple bond is by numbering the longest chain that contains both the carbons of the triple bond starting with the one closest to the bond. The smaller number of the two carbon atoms of the triple bond is used as the triple bond locator. 2. Then use the prefix stem to indicate the number of carbon atoms in the chain & the suffix “ene” ending. 3. Follow rules from “alkanes” to name substituent groups attached to alkenes. If the triple bond is in the center of the chain, the nearest substituent group rule is used to determine where numbering begins If more than 1 triple bond is present, the compound is named diene, triene, etc. Each triple bond is given a locator number.
85
Alkyne Examples C2H2
86
Cyclo Alkanes All carbons are single bonded to two other carbons in a ring structure. To name them: Rings are numbered to give the smallest substituent numbers possible. 2. Largest substituent groups are given the lowest locator number
87
Aromatic Hydrocarbons
Nonpolar hydrocarbons with six membered carbon rings with delocalized electrons The simplest molecule: Benzene: C6H6: six carbon ring with alternating double bonds
88
CycloAlkane Examples
89
Functional Groups Many organic compounds contain groups of atoms known as functional groups, which often determine a molecule’s reactivity. You are responsible for recognizing ALCOHOLS & CARBOXYLIC ACUDS
90
Alcohols The –OH (hydroxyl group) is covalent bonded to C so it does not ionize to produce hydroxide ions To name: Indicate the number of carbon atoms to which the –OH group is attached. 2. Drop the “e” from the name of the alkane, and add the suffix –ol 3. Start counting in the chain closest to the –OH group
91
Alcohols
92
Carboxylic Acids Occur in plants and animals
The COOH group must always be on the end and its “C” is always the #1 C in the chain To name: drop the “e” from the name of the alkane, and add the suffix –oic followed by the word “acid”.
93
Carboxylic Acids
94
Name the following Examples
C4H9OH CH3CH2CH2CH2COOH
95
Structural Isomers Two or more compounds with the same chemical
formula but a different arrangement of atoms in the molecule and thus different properties. There are 2 isomers of butane CH3CH2CH2CH and CH3CH(CH3)CH3 (butane) (2-methylpropane) What are the 5 isomers of hexane?
Similar presentations
© 2025 SlidePlayer.com Inc.
All rights reserved.