Atoms Elements The Periodic Table Nomenclature Democritus Atomism

Atoms, Elements, The Periodic Table & Nomenclature

Democritus & Atomism Developed a theory called “Atomism. ” This theory was originally envisioned by his teacher Leucippus to account for the materialistic nature of the world. “The laughing philosopher” c. 460 BCE (Abdera) The Father of Atomism The atomists held that everything tangible is composed of small indivisible bodies which they called “atoms” and that these atoms move about in an infinite void space.

Antoine Lavoisier Defined a chemical “element” as a substance that cannot be decomposed into simpler substances by chemical means. Created a table of 33 of then known elements. 1743 (Paris) – 1794 (Paris) “The Father of Modern Chemistry” Grouped the elements into four categories based on their physical and chemical properties. These categories were gases, nonmetals, and earths.

Jöns Jakob Berzelius Developed a table of atomic weights in 1828. Introduced the use of letters as symbols for the elements. Determined the atomic weight of 43 elements. First to isolate pure calcium, barium, strontium, silicon, titanium, and zirconium. Swedish chemist 1779 – 1848 Discovered selenium, thorium, and cesium.

Johann Döbereiner In 1817, he proposed “triads, ” or groups of three elements with similar properties. He later published these ideas in 1829. Examples of triads: lithium, sodium, & potassium; calcium, strontium, & barium; chlorine, bromine, & iodine. Discovered that the relative atomic mass of the middle element in each triad was close to the average of the relative atomic masses of the other two elements. German Scientist 1780– 1849

John Newlands Proposed the “Law of Octaves. ” In 1863, he arranged the 62 known elements in order of their atomic weights and observed similarities between the first and ninth and second and tenth elements, etc. 1837 (London) – 1898 H 1 Li 2 Be 3 B 4 C 5 N 6 O 7 F 8 Na 9 Mg 10 Al 11 Si 12 P 13 S 14 Cl 15 K 16 Ca 17 Cr 19 Ti 18 Mn 20 Fe 21 Newlands’ Periodic Table Co & Ni 22 Cu 23 Zn 24 Y 25 In 26 As 27 Se 28 Br 29 Rb 30 Sr 31 Ce & La 33 Zr 32 Bi & Mo 34 Rh & Ru 35 Pd 36 Ag 37 Cd 38 U 40 Sn 39 Sb 41 Te 43 I 42 Cs 44 Ba & V 45 Ta 46 W 47 Nb 48 Au 49 Pt & Ir 50 Os 51 Hg 52 Tl 53 Pb 54 Bi 55 Th 56

Lothar Meyer In 1869, he compiled a periodic table of 56 elements based on the “periodicity” of their properties (e. g. , molar volumes) when arranged in order of increasing atomic weight. German chemist 1830 – 1895

Meyer’s Periodic Table for Molar Volume

Dmitri Mendeleev “Father of the Modern Periodic Table” In 1869, he produced a table based on the atomic weights. Russian Physicist and Chemist 1834 (Tobolsk, Siberia ) – 1907 (St. Petersburg) He actually arranged them such that elements with similar properties were located in the table underneath each other; thus, making it easier to observe the “periodicity. ”

Mendeleev’s Periodic Table

1 2 3 4 5 6 Periods are shown as horizontal rows. All of the elements in a given period have the same number of atomic shells.

Groups or families are shown as vertical columns. There are 18 groups in the periodic table. 1 7 2 3 4 8 5 6 Elements in a group have similar electronic configurations for their valence shell electrons. This is why elements in a group have similar chemical properties.

William Ramsay Discovered argon in 1894. Discovered the noble gases which formed a new group in the periodic table. Awarded the Nobel Prize for Chemistry in 1904. 1852 (Glasgow) – 1916 (High Wycombe)

Henry Moseley In 1914, he determined the atomic number of each of the elements by x-ray scattering. He modified the “periodic law” to indicate that the properties of the elements vary periodically with their atomic number rather than atomic weight. English physicist 1887 – 1915

Henry Moseley He pointed out the existence of missing elements in the periodic table for atomic numbers 43, 61, 72, and 75. Each of these elements, Tc, Pm, Hf, and Re were eventually discovered. He also showed that there are no elements lighter than hydrogen (Z = 1) and that there is no possibility for elements between hydrogen and helium (Z = 2). Both possibilities had been advanced, with some proposals demanding three elements between H and He.

Glenn Seaborg Starting in 1940, he synthesized several of the transuranic elements that occur after uranium in the periodic table. He won the Nobel Prize for Chemistry in 1951 for the discovery of plutonium. American chemist 1912 – 1999 Seaborgium (element 106) is named after him.

rth a E et e n tals M i l i a e al k l M k l A als Periodic Table A Transition metals Lanthanide Series Actinide Series s en H g o l a No s e bl G e as

Nomenclature Rules for naming three classes of compounds: ionic compounds, binary covalent compounds & acids. What type of compound is it? IONIC COMPOUND: Composed of cations (metals or polyatomic ions) and anions (nonmetals or polyatomic ions). TYPE I: Only one type of cation is observed. COVALENT COMPOUND: Nonionic – not composed of cations & anions. Generally, only nonmetals are present. TYPE II: More than one type of cation is observed. TYPE III: Covalent, nonionic. ACID: Produces H+ in water. Typically the hydrogen cation is written first in the chemical formula. ACIDS: Anion does not contain oxygen. OXYACIDS: Anion does contain oxygen.

Rules for Naming Ionic Compounds 1. ) Determine whether or not the compound is ionic. How do you know the compound is ionic in the first place? a. ) If the compound contains a metal, then it is most likely an ionic compound. Metals readily lose electrons to form positive ions, called cations. Ionic compounds almost always contain a metal as a cation and a nonmetal as an anion. b. ) However, not all ionic compounds will contain a metal cation. The cation could be a polyatomic ions, such as NH 4+.

Rules for Naming Ionic Compounds 2. ) Determine whethere is only one type of cation possible (Type I) or whethere are several cations possible (Type II). a. ) If the cation is a polyatomic ion (e. g. , ammonium, NH 4+), then there is only one possible charge and so it is a type I compound. b. ) If the cation is a metal, determine if it forms only one type of cation. Alkali metals (Group 1 A) +1 cation Alkaline earth metals (Group 2 A) +2 cation Transition metals (Group 1 -8 B) often form more than one type of cation.

Rules for Naming Type I Compounds 1. ) The cation is named first and the anion is named second. 2. ) The name of the cation is the same as the name of the element. So both the element Mg and the cation Mg 2+ are called magnesium. (Note: For polyatomic cations, you must memorize the names. ) 3. ) The anion is named by taking the root name of the element and adding the suffix -ide. For example, F is an atom of fluorine and F- is the anion fluoride. (Note: For polyatomic anions, you must memorize the names. ) So Mg. F 2 would be magnesium fluoride.

Rules for Naming Type I Compounds with polyatomic ions Polyatomic ions then resemble molecules in that they contain at least two atoms bound together in a definite arrangement. The steps for naming compounds with polyatomic ions: 1. ) The cation is listed first and the anion second. 2. ) The polyatomic ion names must be memorized. 3. ) No extra prefixes or suffixes are added.

Table of Polyatomic Ions * Sulfur has two anions that are often referred to as persulfate. They are peroxomonosulfate (or peroxymonosulfate) ion, SO 5 2 - and peroxodisulfate (or peroxydisulfate) ion, S 2 O 8 2 -. **The organic anions. *** Thiocyanate and thiosulfate are formed by substituting a sulfur for an oxygen into the cyanate and sulfate ions.

Nomenclature Mnemonic for Remembering “ates” Nick the Camel Ate a Clam Supper and Crepes (for dessert) in Phoenix

Nomenclature Mnemonic for Remembering “ates” Nick the Camel Ate a Clam Supper and Crepes (for dessert) in Phoenix Consonants = Vowels = Oxygen Charge Nick = Nitrate Camel = Carbonate Clam = Chlorate 3 3 3 -1 -2 -1 (Note: Bromate and Iodate are the same as Chlorate. ) Supper = Sulfate Crepes = chromate Phoenix = Phosphate 4 4 4 -2 -2 -3 Polyatomic Ion NO 3 – CO 3 2 Cl. O 3 SO 4 2 Cr. O 4 2 PO 4 3 -

Rules for Naming Type II Compounds Additionally for Type II Compounds: 4. ) Use a roman numeral after the cation to indicate the ionic charge of that cation. So Fe. O would be called iron(II) oxide since the cation is Fe 2+ and Fe 2 O 3 would be iron(III) oxide since the cation is Fe 3+. 5. ) Alternatively, when using traditional names atoms whose valence numbers vary, you add the suffix –ous to the one with the lower valence state and –ic to the one with the higher valence state. So Fe. O would be called ferrous oxide since the cation is Fe 2+ and Fe 2 O 3 would be ferric oxide since the cation is Fe 3+.

Table of Type II Compounds IUPAC copper (I) & copper (II) Root cupr- Traditional -ous Cu+ -ic____ Cu 2+ gold (I) & gold (III) aur- Au+ Au 3+ mercury (I) & mercury (II) mercur- Hg 2 2+ Hg 2+ chromium (II) & chromium (III) chrom- Cr 2+ Cr 3+ manganese (II) & manganese (III) mangan- Mn 2+ Mn 3+ iron (II) & iron (III) ferr- Fe 2+ Fe 3+ cobalt (II) & cobalt (III) cobalt- Co 2+ Co 3+ nickel(II) & nickel (III) nickel- Ni 2+ Ni 3+ tin (II) & tin (IV) stann- Sn 2+ Sn 4+ lead (II) & lead (IV) plumb- Pb 2+ Pb 4+ cerium (III) & cerium (IV) cer- Ce Ce 4+ arsenic (III) & arsenic (V) arsen- As 3+ As 5+ antimony (III) & antimony (V) antimon- Sb 3+ Sb 5+ bismuth (III) & bismuth (V) bismuth- Bi 3+ Bi 5+ 3+

Rules for Naming Binary Covalent Compounds How do you recognize that something is a binary covalent compound (versus an ionic compound)? 1. ) If a compound contains only nonmetals (no metals), then you can be reasonably sure that it is a covalent compound. Note: Some exceptions would be compounds that contain polyatomic ions. For example, ammonium bromide NH 4 Br and ammonium sulfate (NH 4)2 SO 4 are ionic compounds even though they contain only nonmetals.

Type III Compounds: Binary Covalent Compounds 1. ) The first element in the compound is named first using the name of the element. 2. ) The second element is named as though it were an anion (the root name + suffix -ide); even though, we know there are no anions in a covalent compound. 3. ) Prefixes are used to denote the numbers of each atom present. Since there are no formal charges on the atoms in covalent compounds, it is more difficult to predict the proportions that the atoms combine in. (Note: the prefix mono is never used with the first element).

Type III Compounds: Binary Covalent Compounds Examples of binary covalent compounds include water (H 2 O), carbon monoxide (CO), and carbon dioxide CO 2. Prefix monoditritetrapentahexaheptaoctanonadeca- meaning one two three four five six seven eight nine ten The naming convention for binary covalent compounds is as follows: (prefix)-nonmetal + (prefix)-nonmetal root + "-ide. Try naming the compound P 4 O 6.

Rules for Naming Simple Acids and Oxyacids How do we determine if something is an acid? The acids that we will be concerned with naming are really just a special class of ionic compounds where the cation is always H+. Recall that cations are written first in ionic formulas. So if the formula has hydrogen written first, then this usually means that the hydrogen is an H+ cation and that the compound is an acid. When dissolved in water, acids produce H+ ions. These are also called protons, because when the electron is removed from a neutral hydrogen atom, it leaves behind one proton. If the counterion (the anion) to H+ in the acid is a polyatomic ion that contains oxygen (like NO 2 - or PO 43 -), the acid is called an oxyacid. If the anion does not contain oxygen (like F- or CN-), then a different set of rules are used for naming the acid.

Binary acids are binary compounds that contain a hydrogen atom and either a halogen (F, Cl, Br, I) or sulfur (S). It is important to note that nitrogen, phosphorus, and oxygen do not form binary acids with hydrogen. The naming convention for binary acids is as follows: “Hydro-” + nonmetal root + “-ic” + “acid” The nonmetal roots are determined as follows. For the halogens, simply remove the “ine” and for sulfur remove the “ur”. Thus, the roots for fluorine, chlorine, bromine and iodine are fluor-, chlor-, brom-, and iod- ; and for sulfur, sulf-. So to determine the name for HCl: hydro + chlor + ic + acid → hydrochloric acid If the acid is in a gaseous form or an anhydrous form, the "-ic" is replaced by "-ide" and the "acid" suffix is removed.

So, acids are formed by adding protons to atoms or radicals with negative valence numbers. The names of acids that do not contain oxygen are formed like those of binary acids by adding the prefix hydro- to the root name for the element and adding the suffix –ic and the word “acid”. Formula Acid Name_____ HF hydrofluoric acid HCl hydrochloric acid HBr hydrobromic acid HI hydriodic acid HCN hydrocyanic acid H 2 S hydrosulfuric acid HN 3 hydrazoic acid If only one type of oxygen acid is formed, then the name is that of the characteristic element plus the suffix –ic and the word acid. Formula Acid Name___ H 3 BO 3 boric acid H 2 CO 3 carbonic acid H 4 Si. O 4 silicic acid

Acids formed from polyatomic ions have a naming system similar to that of the polyatomic ions themselves. The difference being that for “-ate” we substitute “-ic” and for “-ite” we substitute “ous” and add the word acid. For example, hypochlor-ite then becomes hypochlorous acid; and perchlor-ate becomes perchloric acid. Ion Name Cl. O 2 Cl. O 3 Cl. O 4 - Ion name Acid Formula hypochlorite chlorate perchlorate HCl. O 2 HCl. O 3 HCl. O 4 Acid hypochlorous acid chloric acid perchloric acid Note: The number of hydrogens added to the polyatomic ion is equal to the charge on the cation. Try naming the acids formed by nitrite and nitrate ions, NO 2 – and NO 3 -, respectively.

Organic Compounds Organic compounds contain carbon. All other compounds are defined as inorganic. However, for the sake of convenience, some carbon compounds are considered inorganic: carbon monoxide (CO), carbon dioxide (CO 2), carbon disulfide (CS 2), and those containing the anions: cyanide (CN-), carbonate (CO 3 2 -) bicarbonate (HCO 3 -)

Organic Compounds The alkanes consist only of carbon and hydrogen held together by single bonds. The first four alkanes have common names. The higher ones have names reflecting the Greek/Latin prefixes used in the covalent naming system. Organic Compounds CH 4 C 2 H 6 C 3 H 8 C 4 H 10 C 5 H 12 C 6 H 14 C 7 H 16 C 8 H 18 C 9 H 20 C 10 H 22 Names methane propane butane pentane hexane heptane octane nonane decane The alkenes have a double bond between two of the carbons. Every double bonded carbon can only form two other bonds. So there are two less hydrogens for every corresponding alkene. The alkynes have a triple bond between two of the carbons. So every triple-bonded carbon can only form one other bond.

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For February 3 -5 Read: The Statistical Analysis of Zinc Washers – Text pp 53 -76 Due: Nomenclature – Packet pp 53 -67 (pp 55 -67 extra credit) Dimensional Analysis 1 – Text pp 15 -24 Problems 1, 3, 8, 11, 14, 15, 17, 19, 20, 21 & 22 Do not apply rules of significant figures. Must show work to receive credit. Significant Figures – Text pp 41 -2 & 51 -52 Problem Set 1 & 2 – Do all problems.