1. Periodic Properties: Groups 5A, 6A, and 7A
Group 5A
Elements and Symbols Element Type State
N = Nitrogen Non-metal diatomic gas
P = Phosphorous Non-metal solid
As = Arsenic Metalloid solid
Sb = Antimony Metalloid solid
Bi = Bismuth Metal solid
Some chemistry of the non-metal Group 5A Elements
The elements tend to react to gain 3 electrons to be like noble gas
These elements react with oxygen to form acidic compounds
HNO3 = Nitric Acid H3PO4 = Phosphoric Acid
P4(s) O2(g) > P4O10(s)
P4O10(s) H2O > 4 H3PO4(aq)
c. Important Biological Elements
N is a component of every amino acid (protein) and DNA
P is a component of DNA

3. d. Phosphorous has more than one allotrope
Allotrope = stable solid phase
P4(s) is called “white phosphorous” is tetrahedral, and burns in air
Pred is called “red phosphorous” and is made of chains of P4 tetrahedra
Pblack is called “black phosphorous” and is a crystalline solid
We will be reacting Red Phosphorous with Oxygen today in lab
Don’t bother with the bottle
Burn the phosphorous in the bunsen burner in the hood
Have a distilled water dampened piece of pH paper ready
Put the pH paper (green when damp) in the phosphorous smoke
If it turns red, that indicates the formation of acid
DON’T PUT HOT COMBUSTION SPOON INTO BOTTLE!!!

4. Group 6A
1. Elements and Symbols Element Type State
O = Oxygen Non-metal diatomic gas
S = Sulfur Non-metal solid
Se = Selenium Non-metal solid
Te = Tellurium Metalloid solid
Po = Polonium Metalloid solid
2. Some chemistry of the non-metal Group 6A Elements
The elements tend to react to gain 2 electrons to be like noble gas
20% of the atmosphere and 50% of the crust is O (by mass)
These elements react with oxygen to form acidic compounds
Sulfuric Acid (H2SO4) is the largest volume chemical used in industry
- S(s) O2(g) > SO2(g)
SO2(g) H2O(l) > H2SO3(aq) = sulfurous acid
We will be burning S(s) in the hood to produce H2SO3
Use same procedure as for phosphorous
All waste P and S should be completely burned off of the spoon

5. monoclinic rhombic plastic Sulfur has more than one Allotrope
Two allotropes of solid sulfur have 8-membered rings, but different crystal forms: “monoclinic” and “rhombic”
If liquid sulfur is cooled quickly, it solidifies as chains of sulfur atoms called “plastic sulfur”
monoclinic
rhombic
plastic

6. Sodium Reacts Violently with Chlorine
Group 7A = Halogens (kJ/mol)
1. Elements Element Type State E.A.
F = Fluorine Non-metal diatomic gas, yellow -328
Cl = Chlorine Non-metal diatomic gas, yellow -349
Br = Bromine Non-metal diatomic liquid, brown -325
I = Iodine Non-metal diatomic solid, purple -295
At = Astatine Non-metal radioactive solid
The chemistry of these elements is dominated by their need to add one e-
2 Na(s) Cl2(g) > 2 NaCl(s) large amount of heat
Sodium Reacts Violently with Chlorine

7. X(g) + e- -----> X-(g)
3. Electron Affinity = energy given off when a gaseous element gains an e-
X(g) e > X-(g)
Exothermic process because all elements accept e- due to + nucleus
Adding e- is less favored down a group due to distance from nucleus
Fluorine is so small, that repulsion from other electrons lowers its E.A.
Halogens with more favorable E.A. can take electrons from other halides
Cl Br > 2 Cl Br2
E.A:
Cl2 is reduced; Br- is oxidized
We will be studying this kind of reaction today in lab
Prepare control samples:
I2/H2O toluene = purple color of I2 in toluene
Br2/H2O toluene = orange color of Br2 in toluene
Cl2/H2O toluene = yellow color of Cl2 in toluene I2
Cl2
Br2

8. Run all possible combinations of reactions between Cl/Br/I and observe the color of the toluene when finished
Cl Br > yellow (Cl2) if no reaction; orange (Br2) if reaction
Cl I >
Br Cl >
Br I > orange (Br2) if no reaction; purple (I2) if reaction
I Cl >
I Br >
Use parafilm to cover test tubes to shake them up
All halogen reactions go into a waste beaker in the hood

9. Incident: HF and Trifluoroacetic Acid Burn Incident: HF Exposure