Metals - Found on the left side of the periodic table Includes: All of groups 1 (except H) and 2, also Al (but not B) in group 13. All of the transition elements. The elements to the right of the transition elements The lanthanides and actinides (inner transition metals) Metals tend to lose electrons!

Metallic Properties: Luster Luster: most metals have a silvery white “metallic” colorbecause they reflect light of all wavelengths. Ductile, Ductile, (capable of being drawn out into a wire) Malleable Malleable (can be hammered into thin sheets) semisolids Most room Tº High electrical conductivity & thermal conductivity - Examples: sodium, calcium, gold, aluminum

Nonmetals Found on the right side of the periodic table Nonmetals tend to gain electrons! Nonmetallic Properties: –Poor reflectors of light, –Hard or brittle, some are gases or soft solids –Not malleable or ductile –Do not conduct electricity, –Poor conductor of heat - Examples: carbon, bromine, chlorine, sulfur

Metalloids or Semimetals Found along jagged line on table Metalloids lose or gain electrons depending on "who they're with!“ Mixture of both types of properties, or intermediate type Examples: B, Si, Ge, As, Sb, Te, At (the only metals on the solid "semimetal" line are Al and Po)

Compounds and Chemical Reactions Essentially all elements combine to form compounds Compounds are of two types: –Molecular, formed by shared electrons and consist of electrically neutral, discrete particles called molecules –Ionic – formed by electron transfer and charged particles called ions

Ionic Compounds – ionic crystals that can vary in size…. Molecular compounds – discrete particles or molecules

Chemical formulas are collections of chemical symbols that are used to describe elements and compounds –Free elements are not combined with other elements in a compound Examples: Fe (iron), Na (sodium), and K (potassium)

A chemical formula is a symbolic representation of the composition of a compound in terms of its constituent elements.

Chemical formulas specify the composition of a substance NaCl is composed of the elements sodium and chlorine in a one-to-one (atom) ratio Fe 2 O 3 is composed of the elements iron and oxygen in a two-to-three ratio CO(NH 2 ) 2 expands to CON 2 H 4, but there are good reasons to write some compounds with parentheses Hydrates are crystals that contain water molecules, for example plaster: CaSO 4 2H 2 O –When all the water is removed (by heating), the solid that remains is said to be anhydrous (without water)

Ions and Ionic Compounds Atoms that gain or lose electrons are called ions Positive ions: CATIONSNegative ions: ANIONS Atoms that lose electrons form cations Na  Na + + e – EOS Atoms that gain electrons form anions Cl + e –  Cl –

The charges on many representative elements can be predicted: Metals form cations –The positive charge on the cation is the same as the “A” group number of the metal –Ask: “How many e - needed to lose to reveal noble gas core?” Nonmetals form anions –The negative charge on the anion is equal to the number of spaces to the right we have to move in the periodic table to get to a noble gas –Ask: “How many e - needed to gain to make noble gas core?”

Ion Typically formed

Names and Formulas for Ionic Compounds Ionic compounds form when oppositely charged ions are attracted to each other NaCl Resulting compound is electrically neutral Na + Cl – (+1)+(–1) = 0 Ionic compound names use the cation name followed by the anion name EOS Sodium chloride

Ionic Bonding is the TRANSFER of electrons from one element to another.

Polyatomic Ions EOS Polyatomic ions are charged groups of covalently bonded atoms

Rules for writing Formulas of Ionic Compounds: 1) The positive ion is given first in the formula. 2) The subscripts in the formula must produce an electrically neutral formula unit. 3) The subscripts should be the set of smallest whole numbers possible. 4) The charges on the ions are not included in the finished formula of the substance.

Introduction to Compounds covalent bonds A molecule is a group of two or more atoms held together by covalent bonds. Remember: Ionic Compounds form crystals. The term used for Ionic compounds is "formula unit“ not molecule! oices.com/files/2013/ 04/Water-molecule- panel-1024x409.jpg

Covalent Bond In a Covalent Bond, atoms SHARE electrons to form stable pairs.

Many nonmetals occur as diatomic molecules

There are 7 elements that occur as diatomic molecules in nature: Molecules that contain two atoms bonded together are called diatomic molecules.

Molecular Compounds EOS Ball-and-stick model vs. Space- filling model

Empirical and Molecular Formulas EOS Empirical formula: Empirical formula: the simplest whole number ratio of elements in a compound (covalently bonded) Example: Molecular formula of glucose – C 6 H 12 O 6 EOS The elemental ratio C:H:O is 1:2:1, so the empirical formula is CH 2 O Molecular formula: Molecular formula: the actual number of atoms of elements in a compound

Inorganic compounds are substances not considered to be derived from hydrocarbons and do not have carbon in them. The rules for naming, or nomenclature, of simple inorganic compound is covered now (organic nomenclature is covered later) Binary compounds are compounds comprised of two different elements The goal is to be able to convert between the chemical formula and the name

Formulas and Subscripts in Molecules Subscripts are used when a given atom is used more than once e.g., H 2 O, CO 2, N 2 O, HF, B 2 O 3 The presence of subscripts is reflected in the names of compounds EOS

Binary Molecular Compounds Compounds that are typically comprised of two nonmetallic elements: e.g., CO, NO, HF EOS Molecular formulas are usually written with the more “metallic” first – “metallic” means farther left in the period and lower in the group

The first element in the formula is identified by its English name, the second by appending the suffix –ide to its stem Chemical Name as Name as Symbol Stem First Element Second Element O ox- oxygen oxide S sulf- sulfur sulfide N nitr- nitrogen nitride P phosph- phosphorus phosphide F fluor- fluorine fluoride Cl chlor- chlorine chloride Br brom- bromine bromide I iod- iodine iodide

Many molecular compounds contain hydrogen: Group Noble Period Gas (18) 2 CH 4 NH 3 H 2 O HF Ne 3 SiH 4 PH 3 H 2 S HCl Ar 4 GeH 4 AsH 3 H 2 Se HBr Kr 5 SbH 3 H 2 Te HI Xe Note: The number of hydrogens that combined with the nonmetal equals the number of spaces to the right we have to move to get to the noble gas

The number of each type of atom is specified with Greek prefixes Greek Prefixes mono- = 1 (often omitted) hexa- = 6 di- = 2 hepta- = 7 tri- = 3 octa- = 8 tetra- = 4 nona- = 9 penta- = 5 deca- = 10 Examples: PF 5 = phosphorus pentafluoride HCl = hydrogen chloride N 2 O 5 = dinitrogen pentoxide Note: many compounds have common names, like water for H 2 O.

Names of Binary Compounds The names are further modified by adding prefixes to denote the numbers of atoms Consider the compounds CO and CO 2 EOS

To name a compound, you can use this flowchart: