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Descriptive Chemistry Overview for Exam II

These are overview for Spring 2017, Chem 2C course, but not bad to review.

Group 1: Alkali Metals

  1. Name: Alkali: The metals and their oxides react with water to form OH- to create basic aqueous solutions. Metals: they are metals
  2. Atomic Radius: INCREASES down the group and DECREASES left to right
  3. Electronegativity: DECREASES down the group and INCREASES left to right
  4. Ionization Energy: DECREASES down the group and INCREASES left to right
  5. Metallic Character: INCREASES down the group and DECREASES left to right (think more metallic towards the metals on the left side of the periodic table)
  6. Reactions with H: All metals react with H2 (g) to form ionic hydrides where H behaves like the halogens

2M+X2  2MH

  1. Reactions with O: Forms Oxide Ion (O2-), Peroxide Ion (O22-), or Superoxide Ion (O2-)
  • Oxides

2Li + O2 2Li2O

  • Peroxides

2Na + O Na2O2

  • Superoxides

K + O KO2

Cs + O  CsO2

Rb + O  RbO2

  1. Reactions with H2O: The Alkali Metals are powerful reducing agents (meaning they really want to be oxidized and have very negative Standard Reduction Potentials (Table P2) that reduce H2O and release H2(g). They form strong bases in aqueous solutions

2M + 2H2 2MOH + H2

  • Note: These metals’ oxides can also dissolve in water to give a basic solution. (for example):

Li2O+ H2 2Li+ + 2OH-

2Na2O2 + 2H2 4Na+ + 4OH- + O2

4KO2 + 2H2 4K+ + 4OH- + 3O2

  1. Reactions with N: Only Li reacts with N at room temperature

                                                              i.      6Li + N2   2Li3N

  1. Reactions with Halogens: Forms ionic halides

                                                              i.      2M+X22MX

Group 2: Alkaline Earth Metals

  1. Name: Alkaline: The metals and their oxides react with water to form OH- thus creating a basic solution. Earth: They are more insoluble than their counterparts in group one and do not decompose upon heating. Metals: they are metals
  2. Atomic Radius: INCREASES down the group and DECREASES left to right
  3. Electronegativity: DECREASES down the group and INCREASES left to right
  4. Ionization Energy: DECREASES down the group and INCREASES left to right
  5. Metallic Character: INCREASES down the group and DECREASES left to right (think more metallic towards the metals on the left side of the periodic table)
  6. Reactions with H: M ≠ Be or Mg

M + H2   MH2

  1. Reactions with O: Forms basic anhydrides

2M + O 2MO

  1. Reactions with H2O: Reacts to form bases in aqueous solutions; M ≠ Be; Mg reacts with steam

M + 2H2 M(OH)2 + H2(g)

  1. Reactions with N: This occurs only with extreme difficulty and heat

3M + N2(g)   M3N2

  1. Reactions with Halogens: Reacts to form metal halides; X2= F2, Cl2, Br2, I2

M + X2   MX2

Group 13: The Boron Family

  1. Name: Named after top element of group. Elemental Chemistry changes from non-metal to metal as going down
  2. Atomic Radius: INCREASES down the group and DECREASES left to right
  3. Electronegativity: DECREASES down the group and INCREASES left to right
  4. Ionization Energy: DECREASES down the group and INCREASES left to right
  5. Metallic Character: INCREASES down the group and DECREASES left to right (think more metallic towards the metals on the left side of the periodic table)
  6. Reactions with H: B forms hydrides – it is unusual as it is a nonmetal that typically forms covalent bonds

BH3, B2H6, etc.

  1. Reactions with O:

4M + 3O2(g)   2M2O3

4Al + 3O2   2Al2O3

  1. Reactions with H2O:
  • Al2O3 is an “amphoteric oxide”
    • Reacting as an acid: Al2O3 + 2OH- + 3H2 2Al(OH)4-
    • Reacting as a base: Al2O3 + 6H3O+ + 3H2 2Al(H2O)63+
  1. Reactions with N: N/A
  2. Reactions with Halogens: M = B or Al, X = F, Cl, Br, I

M + 3X  MX3

Group 14: The Carbon Family

  1. Name: Named after top element of group; elemental Chemistry changes from non-metal to metals down the group.
  2. Atomic Radius: INCREASES down the group and DECREASES left to right
  3. Electronegativity: DECREASES down the group and INCREASES left to right
  4. Ionization Energy: DECREASES down the group and INCREASES left to right
  5. Metallic Character: INCREASES down the group and DECREASES left to right (think more metallic towards the metals on the left side of the periodic table)
  6. Reactions with H:

                                                              i.      Ex. C + 2H2  CH4+ other hydrocarbons

  1. Reactions with O: Z = C, Si, Ge

Z + O  ZO2

C + O → CO2

Si + O  SiO2

Ge + O  GeO2

  1. Reactions with H2O: N/A
  2. Reactions with N: N/A
  3. Reactions with Halogens: Z = C, Si, Ge

Z + 2Cl2   ZCl4

Group 15: The Nitrogen Family

  1. Name: Named after top element of group; elemental Chemistry changes from non-metal to metal down the group.
  2. Atomic Radius: INCREASES down the group and DECREASES left to right
  3. Electronegativity: DECREASES down the group and INCREASES left to right
  4. Ionization Energy: DECREASES down the group and INCREASES left to right
  5. Metallic Character: INCREASES down the group and DECREASES left to right (think more metallic towards the metals on the left side of the periodic table)
  6. Reactions with H:

Example. The Haber Process:

\[N_2 + 3H_2  \rightleftharpoons NH_3\]

g.      Reactions with O: Form the NOxs (means N can have different oxidation states) and oxides

  • Nitrogen:

N2O5, NO2, N2O3, NO, N2O

2NO + O  2NO2

  • Phosphorus

Limited O2: P4 + 3O2   P4O6

Excess O2: P4 + 5O2   P4O10

h.      Reactions with H2O: Phosphorous oxides form acids in water

P4O6+ 6H2 4H3PO3

i.        Reactions with N:

N2(g)

j.        Reactions with Halogens: N/A

Group 16: The Oxygen Family (The Chalcogens)

  1. Name: “Ore Former” – They can form ore oxides with other elements
  2. Atomic Radius: INCREASES down the group and DECREASES left to right
  3. Electronegativity: DECREASES down the group and INCREASES left to right
  4. Ionization Energy: DECREASES down the group and INCREASES left to right
  5. Metallic Character: INCREASES down the group and DECREASES left to right (think more metallic towards the metals on the left side of the periodic table)
  6. Reactions with H: Form compounds with H

H2O, H2O2, H2S

g.      Reactions with O: Form compounds of S with O

H2SO4, H2SO3

SO2, SO3

h.      Reactions with H2O:

Oxides of P in H2O

i.        Reactions with N:

NO

j.        Reactions with Halogens: N/A

Group 17: The Halogens

  1. Name: “Salt Formers” – They form salts when they react with metals
  2. Atomic Radius: INCREASES down the group and DECREASES left to right
  3. Electronegativity: DECREASES down the group and INCREASES left to right
  4. Ionization Energy: DECREASES down the group and INCREASES left to right
  5. Metallic Character: INCREASES down the group and DECREASES left to right (think more metallic towards the metals on the left side of the periodic table)
  6. Reactions with H: Form hydrogen halides, X = F, Cl, Br, I

H2(g) + X2(g)   2HX(g)

  1. Reactions with O: Form different Halogen oxoacids

HXO4, X = Cl, Br, I

HXO3, X = Cl, Br, I

HXO2, X = Cl

HXO, X = Cl, Br, I

  1. Reactions with H2O: Halides are acidic when dissolved in water

HCl, HBr, HI, HF

  1. Reactions with N: N/A
  2. Reactions with Halogens: Can form interhalogens

BrCl, BrF3, ClF5

Cl2 + 5F2   2ClF5

Group 18: The Noble Gases

  1. Name: These gases were previously thought to be inert but they do react selectively with some elements. Since they are too good to react with most elements they are “noble”.
  2. Atomic Radius: INCREASES down the group and DECREASES left to right
  3. Electronegativity: DECREASES down the group and INCREASES left to right
  4. Ionization Energy: DECREASES down the group and INCREASES left to right
  5. Metallic Character: INCREASES down the group and DECREASES left to right (think more metallic towards the metals on the left side of the periodic table)
  6. Reactions with H: N/A
  7. Reactions with O: Only Xe reacts with O at high temperatures

Xe + O2(g)   XeO2

  1. Reactions with H2O: N/A
  2. Reactions with N: N/A
  3. Reactions with Halogens: Only Xe reacts with F at high temperatures (e.g.)

Xe + F2   XeF2

Kr + F2   KrF2 (very unlikely but at high temperatures)