22.1+Periodic+Trends+and+Chemical+Reactions

=Periodic Trends=
 * Know trends of ionization energy, electronegativity, nonmetallic/metallic character, atomic radius




 * Another way to picture this information (electron affinity also included in this model, though not mentioned in the section)-
 * Here, the trend increases in the direction of its arrows



Using Trends
=Chemical Reactions=
 * Nonmetals have higher electronegativities than metals --> causes the formation of ionic solids
 * Compounds formed between nonmetals are **molecular**
 * Usually gases, liquids, or volatile solids at room temperature
 * Elements in the 3rd period and below can accomodate a larger number of bonds
 * The first element in a group (upper most element of a group) forms pi bonds more easily (most significant in 2nd row, non-metals)
 * Accounts for stronger bonds in molecules containing these elements
 * Major factor in determining the structures of compounds formed from these elements
 * Elements in periods 3-6 tend to form only single bonds
 * You should already know
 * 1) Combustion
 * 2) Metathesis (Double Replacement)
 * 3) Bronsted-Lowry acid-base (proton transfer)
 * 4) Lewis acid-base
 * 5) Redox

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 * If you forgot everything you know about reactions: (synthesis, decomposition, single and double displacement, combustion)

Combustion with O2

 * Hydrogen containing compounds form water
 * Carbon containing compounds form carbon dioxide
 * Unless there is not enough CO2, then CO or C will form
 * Nitrogen containing compounds form N2
 * All three types summed up in equation:
 * 4 CH3NH2 (g) + 9 O2 (g) à 4 CO2 (g) + 10 H2O (g) + 2 N2 (g)
 * The formation of CO2, H2O, and N2 shows the high thermodynamic stabilities of these molecules
 * Metals + O2 --> metallic oxides
 * Nonmetallic hydrides + O2 --> H2O + nonmetal oxides
 * Nonmetallic sulfides + O2 --> SO2 + nonmetal sulfides

Bronsted-Lowry Acid-Base

 * Acid = proton //donor;// Base = proton //reciever//
 * Weaker acid = stronger conjugate base
 * H2, OH-, NH3, CH4 : Have NO tendency to act as acids in water
 * Therefore, extremely strong bases are formed by removing one proton: H-, O^2-, NH3^-
 * These bases react easily with water to form OH-

Reactions (information not in section but in packets from the beginning of the year)
Anhydrides Complex Ions Decomposition Synthesis Metathesis Redox Hydrolysis (Reaction with water)
 * Metallic hydrides + H2O --> H2(g) + matallic hydroxides
 * Soluble nonmetallic oxides + H2O --> acids (Nonmetal oxidation number doesn't change)
 * Soluble metallic oxides + H2) --> bases (metallic hydroxides)
 * Complex ion solution + strong acid solution --> metal ion or metal ppt and ligand ion
 * Electrolysis of binary ionic compound (molten) --> metal and nonmetal components
 * Binary molecular compound + nonmetal contained in compound --> single compound
 * Metal + nonmetal --> binary ionic compound
 * Nonmetal oxides + H2O --> acid
 * Soluble metallic oxides + H2) --> bases (metallic hydroxides)
 * AX + BY --> AY + BX
 * Apply solubility rules!
 * If ppt forms- products include new solid
 * No ppt formed- products include ions
 * Acid + base --> H2O(l) + salt (neutralization)
 * H2S(g) + 2 KOH(aq) --> 2 H2O(l) K2S(aq)
 * Common gases formed include **H2S, SO2, CO2, NH3**
 * Very common on AP test, be familiar with formation of these 4
 * Metal sulfides + any acid --> H2S(g) + salt
 * Metal sulfites + any acid --> SO2(g) + H2O(l) + salt
 * Metal carbonates + any acid --> CO2(g) + H2O(l) + salt
 * Ammonium salts + soluble strong hydroxide + heat --> NH3(g) + H2O(l) + salt
 * Binary molecular compound + nonmetal contained in compound --> single compound
 * Active fere halogens + compound with less active halide ions --> halogen and halide compound
 * Oxidizing agent = substance with higher reduction potential
 * salt + H2O --> acid + base
 * NH4^+ + Cl- + H2O --> H+ + Cl- + NH4OH
 * Salt of a strong acid + weak base --> acidic solution
 * Salt of a weak acid + strong base --> basic solution
 * Salt of a strong acid + salt of a strong base **never undergo hydrolysis**- resulting solution is always neutral
 * Salt of a weak acid + salt of a weak base or neutral solution --> result depends on Ka's and Kb's of acids and bases formed during hydrolysis

Sample Exercise 22.2, p. 934

 * Predict the products and balance the equations:
 * CH3NHNH2(g) + O2(g) -->
 * Mg3P2(s) + H2O(l) -->
 * Spoiler alert- here are the answers.
 * 2 CH3NHNH2(g) + 5 O2(g) --> 2 CO2(g) + 6 H2O(g) + 2 N2(g)
 * Mg3P2(s) + 6 H2O(l) --> 2 PH3(g) + 3 Mg(OH)2(s)