Chapter 2 Nomenclature

Periodic Table

Metals Conductors Lose electrons Malleable and ductile

Nonmetals Brittle Gain electrons Covalent bonds

Semi-metals or Metalloids

Alkali Metals

Alkaline Earth Metals

Halogens

Transition metals

Noble Gases

Inner Transition Metals

+1 +2 -3 -2 -1

Periodic Table Periodic table is organized based on the properties that elements have in common with one another. Groups: Elements in the same vertical columns are in the same group have similar chemical properties. Group 1A: Alkali metals: Li, Na, K, Rb, Cs, Fr Group 2A: Alkaline earth metals: Be, Mg, Ca, Sr, Ba, Ra Group 7A: Halogens: F, Cl, Br, I, At (astatine) Group 8A: Noble gases: He, Ne, Ar, Kr, Xe, Rn (radon)

Periodic Table Periods: The horizontal rows of elements in the periodic table are called periods. First period: horizontal row one contains H and He Second period: row two contains Li through Ne Letters in the boxes are the symbols for the elements Abbreviations are based on the current element names or the original names. The number above each symbol is the atomic number (number of protons)

Periodic Table Most of the elements are metals in the periodic table. Metals: Conduction of heat and electricity, malleability, ductility, lustrous, form positive ions Nonmetals: appear in the upper right hand corner of the periodic table except hydrogen. Nonmetals lack the physical properties that characterize the metal, gain electrons in chemical reaction and form negative ions, form covalent bond to each other.

Naming Compounds Binary Compounds: Compounds composed of two elements Binary Ionic Compounds (Type I): contains a positive ion (cation) always written first in the formula and a negative ion (anion) Rules: The cation is always named first and the anion second A monatomic (meaning one atom) cation takes its name from the name of the element A monatomic anion is named by taking the root of the element name and adding –ide

Naming compounds Two types Ionic - metal and non metal or polyatomics. Covalent- non-metals.

Ionic compounds If the cation is monoatomic- Name the metal (cation) just write the name. If the cation is polyatomic- name it. If the anion is monoatomic- name it but change the ending to –ide. If the anion is poly atomic- just name it.

Covalent compounds Two words, with prefixes. Prefixes tell you how many. mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca First element whole name with the appropriate prefix, except mono. Second element, -ide ending with appropriate prefix.

Ionic compounds If the cation is monoatomic- Name the metal (cation) just write the name. If the cation is polyatomic- name it If the anion is monoatomic- name it but change the ending to -ide If the anion is poly atomic- just name it from a table.

Ionic Compounds Have to know what ions they form CaS K2S AlPO4 K2SO4 FeS CoI3

Some Polyatomic Ions (Table 2.3) 2.7

Naming compounds Binary Ionic Compounds (Type II): Metals that form more than one type of positive ion. Fe2+ and Fe3+ Transition metals form several positive oxidation states Charge on the metal ion must be specified Roman numeral indicates the charge of the cation. Iron (II) chloride and iron (III) chloride The ion with the higher charge has a name ending in –ic and the one with the lower charge has a name ending in –ous; ferrous chloride and ferric chloride

Naming Compounds Ionic Compounds with Polyatomic Ions: Need to know the names of the polyatomic ions (Table 2.5). NH4+  ammonium, SO42-  sulfate Na2SO4 Sodium sulfate KH2PO4 Potassium dihydrogen phosphate Fe(NO3)3 Iron(III) nitrate CsClO4 Cesium perchlorate NaOCl sodium hypochlorite Al2(Cr2O7)3 Aluminum dichromate Sr(CN)2 Strontium cyanide

Naming compounds Binary Covalent Compounds (Type III): Formed between two nonmetals Rules: The first element in the formula is named first, using the full element’s name Second element is name as if it were an anion Use prefixes to denote the number of atoms present Never use mono – prefix for naming the first element

Molecular compounds nonmetals OR nonmetals + metalloids common names H2O, NH3, CH4, C60 element further left in periodic table is 1st element closest to bottom of group is 1st if more than one compound can be formed from the same elements, use prefixes to indicate number of each kind of atom last element ends in ide 2.7

P2O5 ==> diphosphorus pentoxide S2Cl4 ==> disulfur tetrachloride CO ==> carbon monoxide, not monocarbon monoxide P2O5 ==> diphosphorus pentoxide S2Cl4 ==> disulfur tetrachloride NO2 ==> nitrogen dioxide N2O5 ==> dinitrogen penoxide

Chemical Nomenclature Ionic Compounds often a metal + nonmetal anion (nonmetal), add “ide” to element name BaCl2 barium chloride K2O potassium oxide Mg(OH)2 magnesium hydroxide KNO3 potassium nitrate 2.7

Transition metal ionic compounds indicate charge on metal with Roman numerals FeCl2 iron(II) chloride 2 Cl- -2 so Fe is +2 FeCl3 3 Cl- -3 so Fe is +3 iron(III) chloride Cr2S3 3 S-2 -6 so Cr is +3 (6/2) chromium(III) sulfide 2.7

Molecular Compounds HI hydrogen iodide NF3 nitrogen trifluoride SO2 sulfur dioxide N2Cl4 dinitrogen tetrachloride TOXIC! NO2 nitrogen dioxide N2O dinitrogen monoxide Laughing Gas 2.7

An acid can be defined as a substance that yields hydrogen ions (H+) when dissolved in water. HCl Pure substance, hydrogen chloride Dissolved in water (H+ Cl-), hydrochloric acid An oxoacid is an acid that contains hydrogen, oxygen, and another element. HNO3 nitric acid H2CO3 carbonic acid H2SO4 sulfuric acid 2.7

A base can be defined as a substance that yields hydroxide ions (OH-) when dissolved in water. NaOH sodium hydroxide KOH potassium hydroxide Ba(OH)2 barium hydroxide 2.7

Common Cations and Anions

Formulas from Names Name Chemical Formula Diphosphorus pentasulfide P2S5 (two non metals) Cesium peroxide Cs2O2 (Cs1+, O22-) Aluminum fluoride AlF3 (Al3+, F-1) Vanadium (v) fluoride VF5 (V5+, F-1) Dioxygen difluoride O2F2 (two non metals) Gallium oxide Ga2O3 (Ga3+, O2-) Ammonium dichromate (NH4)2Cr2O7 (NH4+, Cr2O72-) Cupric phosphate Cu3(PO4)2 (Cu2+, PO43-)

Flowchart for Naming Binary Compounds

Acids When dissolved in water produce a solution containing free H+ ions (protons) An acid is a molecule with one or more H+ ions attached to an anion If the anion does not contain oxygen, the acid is named with the prefix hydro – and the suffix –ic HCl Hydrochloric acid HCN Hydrocyanic acid

Acids If the anion contains oxygen, the acidic name is formed from the root name of the anion with the suffix of –ic or –ous depending on the anion HNO3 Nitric acid (Nitrate anion) H2SO4 Sulfuric acid (Sulfate anion) H3PO4 Phosphoric acid (Phosphate anion) HC2H3O2 Acetic acid (Acetate anion) H2SO3 Sulfurous acid (sulfite anion) HNO2 Nitrous acid (nitrite anion)