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Atoms, Elements, The Periodic Table & Nomenclature.

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Presentation on theme: "Atoms, Elements, The Periodic Table & Nomenclature."— Presentation transcript:

1 Atoms, Elements, The Periodic Table & Nomenclature

2 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 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. “The laughing philosopher” c. 460 BCE (Abdera) The Father of Atomism

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

4 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. Discovered selenium, thorium, and cesium. Swedish chemist 1779 – 1848

5 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

6 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. H 1 Li 2 Be 3 B 4 C 5 N 6 O 7 F8 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 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 1837 (London) – 1898 Newlands’ Periodic Table

7 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

8 Meyer’s Periodic Table for Molar Volume

9 Dmitri Mendeleev “Father of the Modern Periodic Table” Russian Physicist and Chemist 1834 (Tobolsk, Siberia ) – 1907 (St. Petersburg) In 1869, he produced a table based on the atomic weights. 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.”

10 Mendeleev’s Periodic Table

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

12 Groups or families are shown as vertical columns. There are 18 groups in the periodic table. Elements in a group have similar electronic configurations for their valence shell electrons. This is why elements in a group have similar chemical properties. 1 2 345 6 7 8

13 William Ramsay 1852 (Glasgow) – 1916 (High Wycombe) 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.

14 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

15 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. 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.

16 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. Seaborgium (element 106) is named after him. American chemist 1912 – 1999

17 Transition metals Lanthanide Series Actinide Series Alkali Metals Alkaline Earth Metals Halogens Noble Gases Periodic Table

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

19 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 +.polyatomic ions

20 2.) Determine whether there is only one type of cation possible (Type I) or whether there are several cations possible (Type II). Rules for Naming Ionic Compounds a.) If the cation is a polyatomic ion (e.g., ammonium,polyatomic ion 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 1A) +1 cation Alkaline earth metals (Group 2A) +2 cation Transition metals (Group 1-8B) often form more than one type of cation.

21 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 MgF 2 would be magnesium fluoride. Rules for Naming Type I Compounds

22 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. Rules for Naming Type I Compounds with polyatomic ions

23 * 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. Table of Polyatomic Ions

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

25 Consonants = Vowels = Polyatomic Oxygen ChargeIon Nomenclature Mnemonic for Remembering “ates” Nick the Camel Ate a Clam Supper and Crepes (for dessert) in Phoenix Nick = Nitrate3 -1NO 3 – Camel = Carbonate3 -2CO 3 2- Clam = Chlorate3 -1ClO 3 - (Note: Bromate and Iodate are the same as Chlorate.) Supper = Sulfate4 -2SO 4 2- Crepes = chromate4 -2CrO 4 2- Phoenix = Phosphate4 -3PO 4 3-

26 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 FeO 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 FeO 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+.

27 IUPACTraditional Root-ous-ic____ copper (I) & copper (II)cupr-Cu + 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 3+ 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+ Table of Type II Compounds

28 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.

29 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).

30 Prefixmeaning mono-one di-two tri-three tetra-four penta-five hexa-six hepta-seven octa-eight nona-nine deca-ten Examples of binary covalent compounds include water (H 2 O), carbon monoxide (CO), and carbon dioxide CO 2. Type III Compounds: Binary Covalent Compounds The naming convention for binary covalent compounds is as follows: (prefix)-nonmetal + (prefix)-nonmetal root + "-ide. Try naming the compound P 4 O 6.

31 Rules for Naming Simple Acids and Oxyacids 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 4 3- ), 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. How do we determine if something is an acid?

32 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.

33 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”. FormulaAcid Name_____ HFhydrofluoric acid HClhydrochloric acid HBrhydrobromic acid HIhydriodic acid HCNhydrocyanic acid H 2 Shydrosulfuric 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. FormulaAcid Name___ H 3 BO 3 boric acid H 2 CO 3 carbonic acid H 4 SiO 4 silicic acid

34 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. IonIon nameAcid FormulaAcid Name ClO - hypochloriteHClOhypochlorous acid ClO 2 - chloriteHClO 2 chlorous acid ClO 3 - chlorateHClO 3 chloric acid ClO 4 - perchlorateHClO 4 perchloric acid Try naming the acids formed by nitrite and nitrate ions, NO 2 – and NO 3 -, respectively. Note: The number of hydrogens added to the polyatomic ion is equal to the charge on the cation.

35 Organic Compounds 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 contain carbon. All other compounds are defined as inorganic.

36 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 CompoundsNames CH 4 methane C 2 H 6 ethane C 3 H 8 propane C 4 H 10 butane C 5 H 12 pentane C 6 H 14 hexane C 7 H 16 heptane C 8 H 18 octane C 9 H 20 nonane C 10 H 22 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. Organic Compounds

37 I Might Pass Maybe 0002 Chemistry Song (to the tune of I Will Follow You Into the Dark by Death Cab for Cutie) Remember that “Ate Beats Ite!”… …and hydroxide! OH - Listen here! Y’all know…

38 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 pp41-2 & 51-52 Problem Set 1 & 2 – Do all problems.

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