Experiment 9 – The Periodic Table

1. Experiment 9 – The Periodic Table

3. Concept: • The relationship between the electronic configuration and the chemical properties of elements is most readily expressed in terms of the periodic table. The elements are arranged in the table in the order of increasing atomic numbers in horizontal rows, called periods of such length that elements with similar properties recur periodically. • The elements with similar chemical properties are arranged in vertical columns called groups or families and they have the same number of valence electrons. Elements found in the same horizontal rows have the same number of energy levels but cannot be expected to behave in similar ways.

4. Objectives: 1.) To examine the properties of elements in various group. 2.) To observe the reactions of compounds of elements that belong to the same group in the periodic table.

5. Materials and equipments: • Beaker • Blue & red litmus papers • Bunsen burner • Corks • Crucible tong • Evaporating dish • Glass tubing • Graduated Cylinder • Pipette • Rubber aspirator • Sand paper/Triangular file • Test tubes • Tripod • Wire gauze

6. Reagents: • 0.1M AlCl3 • １M HCl • 1M NaOH • BaCO3 • CaCO3 • CaO • Concentrated HNO3 • Copper wire • Distilled wire • K2CO3 • Magnesium ribbon • Na2CO3 • Phenolphthalein • Sulfur Powder

7. Procedures: A.) 1.) Place 3mL of CuSO4 solution in a test tube. Take note of its color. 2.) Add 1mL of NH4OH solution to the CuSO4 solution. Observe and record what happens. B.) 1.) Clean a 2-cm piece of Cu wire and a 2-cm piece of Mg ribbon with sand paper. Get a small pinch each of Al metal turning and iron filings. 2.) Place 5mL HCl in each of four test tubes. *CAUTION! HCl can damage skin, eyes, and clothes. Pour carefully* 3.) Add the metals separately to the test tubes. Label each test tube with the name of the metal added. 4.) Observe what happens in each tube. Record any change in the color or appearance of the metal pieces. Record observations on the data chart. C.) 1.) Place 3mL of ZnSO4 in a test tube. Add 1mL of BaCl2 to it. Describe and record what happens.

8. Reaction of active metals with water: • Group I-A metal + water →Base + Hydrogen ions 1.) Group I - 2Na + H2O → 2NaOH + H2↑ = More - 2 K +H2O → 2KOH +H2↑ = reactive because rxn occurs at RT only. • Group II-A metal + water → Base Mg + O2 → MgO heat 2.) Group 2 – MgO + H2O → Mg[OH]2 + H2↑(occurs at high Boiling temp.) turns to fuschia solution w/ phenolphthalein.

9. Properties of carbonates of group I-A & group II-A elements: • Group I-A Carbonates are soluble in water. Na2Co3 + H2O → soluble Group IA elements – more reactive K2Co3 + H2O → Soluble • Group II-A Carbonates are insoluble in water. CaCo3 + H2O → insoluble Group IIA elements – less reactive BaCO3 + H2O → insoluble

10. Properties of metal Oxides: • Group II-A Metallic + Water → Base Mg + O2 → MgO + H2O → Mg [OH]2 + H2↑ + phenolphthalein ↓ Colorless to fuschia pink – Base CaO + H2O → Ca[OH]2+H2↑ + Phenolphthalein ↓ fuschia pink – Base

11. Properties of non-metal oxides: • Group V-A and VI-A Non – metallic oxides + water → Acid S + O2 → SO2 + H2O → H2SO3+ pH(BLP to RLP)→pink – Acid Burning (Yellow Gas) (Sulfurous acid) HNO3 + Cu → HNO2 + CuO + pH (moist BLP to RLP) → pink – Acid (nitrous acid (Copper oxide *green*) *brown*)

12. Metalloid property: AlCl3 + 6H2O → Al(H2O)6+3 + 3CL hydrated Aluminum ion Al(H2O)6+3 + H2O → Al(H2O)5OH+2+ H3O(hydronium) Acid Base Base Acid (hydrated hydrated Aluminum ion) Aluminum ion BLP AlCl3 → BLP – Acidic + HCl → – Acidic RLP AlCl3 → RLP – No change + NaOH → - Basic Metalloid elements such as that of aluminum when combined with other compounds can act both as an acid and as a base.

13. Thank You  Group 5 AAPD1-I