QUIZE 2 Define Ionization Energy. Write trends of Ionization Energy in periodic table, and why? Write the reaction between lithium Li and nitrogen. As you move up and to the right on the periodic table: A. atomic radius increases and electronegativity increases B. atomic radius decreases and electronegativity increases C. atomic radius increases and electronegativity decreases D. atomic radius decreases and electronegativity decreases Dr.Riham Hazzaa 1

Chemistry of Nonmetals 2Dr.Riham Hazzaa

The Chemistry of Oxygen ( Group VI) The electron configuration of an oxygen atom 1s 2 2s 2 2p 4 suggests that neutral oxygen atoms can achieve an octet of valence electrons by sharing two pairs of electrons to form an O=O double bond, as shown in the figure below. According to this Lewis structure, all of the electrons in the O 2 molecule are paired. 3 Dr.Riham Hazzaa

1.Oxygen as an Oxidizing Agent Each O 2 molecule must gain four electrons to satisfy the octets of the two oxygen atoms without sharing electrons 4 Dr.Riham Hazzaa

Oxygen is the perfect example of an oxidizing agent because it increases the oxidation state of almost any substance with which it reacts. In the course of its reactions, oxygen is reduced. The substances it reacts with are therefore reducing agents. C(s)+O2(g)O2(g)CO 2 (g) H2OH2O 4 Fe(s)+3 O 2 (g)2 Fe 2 O 3 (s) +3 H 2 O 5 Dr.Riham Hazzaa

2. Peroxides The O 2 2- ion is called the peroxide ion The easiest way to prepare a peroxide is to react sodium or barium metal with oxygen. 2 Na(s)+O2(g)O2(g)Na 2 O 2 (s) Ba(s)+O2(g)O2(g)BaO 2 (s) 6 Dr.Riham Hazzaa

When these peroxides are allowed to react with a strong acid, hydrogen peroxide (H 2 O 2 ) is produced. The Lewis structure of hydrogen peroxide contains an O-O single bond BaO 2 (s)+2 H + (aq)Ba 2+ (aq)+H 2 O 2 (aq) 7 Dr.Riham Hazzaa

Methods of Preparing O 2 1.By decomposing a dilute solution of hydrogen peroxide with dust or a metal surface as the catalyst. 2.By passing an electric current through water. 2 H 2 O 2 (aq)O2(g)O2(g)+2 H 2 O(l) electrolysis 2 H 2 O(l)2 H 2 (g)+O2(g)O2(g) 8 Dr.Riham Hazzaa

3.By heating potassium chlorate (KClO 3 ) in the presence of a catalyst until it decomposes. 4.By reacting hydrogen peroxide with a strong oxidizing agent, such as the permanganate ion, MnO H 2 O 2 (aq)+2 MnO 4 - (aq)+6 H + (aq)2 Mn 2+ (aq)+5 O 2 (g)+8 H 2 O(l) MnO 2 2 KClO 3 (s)2 KCl(s)+3 O 2 (g) 9 Dr.Riham Hazzaa

The Halogens Group VIIA There is a regular increase in many of the properties of the halogens as we proceed down the column from fluorine to iodine, including the melting point, boiling point, intensity of the color of the halogen, the density of the element. 10 Dr.Riham Hazzaa

On the other hand, there is a regular decrease in the ionization energy as we go down this column. As a result, there is a regular decrease in the oxidizing strength of the halogens from fluorine to iodine. This trend is mirrored by an increase in the reducing strength of the corresponding halides. I - > Br - > Cl - > F - reducing strength F 2 > Cl 2 > Br 2 > I 2 oxidizing strength 11 Dr.Riham Hazzaa

Methods of Preparing the Halogens from their Halides The halogens can be made by reacting a solution of the halide ion with any substance that is a stronger oxidizing agent. Iodine can be made by reacting the iodide ion with either bromine or chlorine. Bromine was prepared by reacting bromide ions with a solution of Cl 2 dissolved in water. 2 I - (aq)+Br 2 (aq)I 2 (aq)+2 Br - (aq) +Cl 2 (aq)Br 2 (aq)+2 Cl - (aq) 12 Dr.Riham Hazzaa

To prepare Cl 2, we need a particularly strong oxidizing agent, such as manganese dioxide (MnO 2 ). 2 Cl - (aq)+MnO 2 (aq)+4 H + (aq)Cl 2 (aq)+Mn 2+ (aq)+2 H 2 O(l) 13 Dr.Riham Hazzaa

The Hydrogen Halides (HX) Several of the hydrogen halides can be prepared directly from the elements. Mixtures of H 2 and Cl 2, react with explosive violence in the presence of light to form HCl. Hydrochloric acid is prepared by reacting table salt with sulfuric acid, and hydrofluoric acid is prepared from fluorite and sulfuric acid. H2(g)H2(g)+Cl 2 (g)2 HCl(g) 2 NaCl(s)+H 2 SO 4 (aq)2 HCl(aq)+Na 2 SO 4 (aq) CaF 2 (s)+H 2 SO 4 (aq)2 HF(aq)+CaSO 4 (aq) 14 Dr.Riham Hazzaa

Common Oxidation Numbers for the Haloge ns Oxidation Number Examples CaF 2, HCl, NaBr, AgI 0 F 2, Cl 2, Br 2, I 2 +1 HClO, ClF +3 HClO 2, ClF 3 +5 HClO 3, BrF 5, BrF 6 -, IF 5 +7 HClO 4, BrF 6 +, IF 7 15 Dr.Riham Hazzaa