The Periodic Table w Developed by Dmitri Mendeleev from many observations that culminated in w Atoms are arranged in increasing atomic number and periodic physical and chemical properties. w Groups - elements in the same column of the table. Generally have similar chemical and physical properties.

Periodic Table w Periods - elements in the same horizontal line that tend to vary in properties from left to right. w Metals - Generally found on the left side of the table. w Non-Metals - Generally found on the right side of the table. w Metalloids - those elements that fall between metals and non-metals along the Zintl Line.

Properties of Elements w Metals - luster, high electrical and heat conductivity,( all except mercury are solid at room temp.), malleability and ductility. w Non-Metals- brittle, non- conductive, dull in appearance, some are solid, liquid and gaseous. w Metalloids - properties fall between those of metals and non-metals.

Important Groups to Note w 1 (1A )= Alkali Metals Li, Na, K, Rb, Cs, Fr w 2 (2A) = Alkaline Earth MetalsBe, Mg, Ca, Sr, Ba, Ra w 16 (6A) = Chalcogens O, S, Se, Te, Po w 17 (7A) = Halogens F, Cl, Br, I, At w 18 (8A) = Noble gases (Inert Gases) He, Ne, Ar, Kr, Xe, Rn

Important Series and Groups to Note w Transition Metals - those elements found in groups 3B through 2B (3-12) d filling orbitals. w Lanthanide Series - include elements numbers 58 through 71. f filling orbitals. w Actinide Series - include elements number 90 through 103. f filling orbitals. w Main Group Elements - All other elements that are s and p filling orbitals.

Molecules and Molecular Compounds w Molecules - an assembly of two or more atoms tightly bound together. w Chemical Formula - The symbols of elements present in the molecule and a subscript which tells the number of atoms in the formula. w Ex. H 2 O, C 6 H 12 O 6, CoCl 2

Diatomic Molecules w Any molecule that is made up of two atoms. w Memorize these Diatomics. w H 2, O 2, N 2, Cl 2, Br 2, I 2, F 2 w A common moniker to remember them by is HONCLBRIF, make sense to you?? w or “The Magnificent Seven”

Diatomic Molecules “The Magnificent Seven” These seven elements occur naturally as molecules containing two atoms

Molecular Compounds w Compounds that are composed of molecules, and contain more than one type of atom. w Ex. Water (H 2 O), Sugar (C 12 H 22 O 11 ) w Most molecular substances that we encounter contain only nonmetals.

Molecular and Empirical Formulas w Molecular Formula - chemical formulas that indicate the actual numbers and types of atoms in a molecule. w Empirical Formula - chemical formulas that give only the relative number of atoms of each type, the subscripts are always the smallest whole number ratios. w Ex. Molecular Formula = C 6 H 12 O 6 6:12:6 Empirical Formula = CH 2 O, 1:2:1

Picturing Molecules w Structural Formulas - Show which atoms are attached to each within the molecule. w Four types are: 1) structural formula - no geometry shown 2) perspective drawing - gives some sense of 3-dimensional shape 3) ball and stick model - 3 dimensional model to give a better idea of actual structure. 4) Space filling model - gives an accurate depiction of what the molecules would look like if they where scaled up.

Ions w A charged particle that is the result of the gain or loss of an electron. ( may be monatomic or polyatomic) w Cation - an ion with a positive charge w Anion - an ion with a negative charge w polyatomic ions - ions which consist of atoms that are joined as a molecule but overall have a charge. Ex. NO 3 -1

Ionic Compounds w A compound that contains positively and negatively charged ions. w Result from the transfer of electrons. w Generally combinations of metals and nonmetals. w Molecular compounds in contrast are generally composed of nonmetals only.