Metals of the side subgroup of group I. Copper
Copper is in period 4, side subgroup of group I (Z = 29, [Ar] 3d¹⁰ 4s¹); in compounds it shows mostly +2, sometimes +1. It stands after hydrogen in the activity series, so it does not displace hydrogen from water or from dilute HCl and H₂SO₄. Ores: chalcocite Cu₂S, chalcopyrite CuFeS₂, cuprite Cu₂O, malachite (CuOH)₂CO₃; in Uzbekistan it is processed at the Almalyk mining and metallurgical combine. The ore is roasted and then Cu₂O is reacted with Cu₂S: 2Cu₂S + 3O₂ → 2Cu₂O + 2SO₂ and 2Cu₂O + Cu₂S → 6Cu + SO₂; pure copper is obtained by electrolysis. Heated, copper gives black CuO: 2Cu + O₂ → 2CuO; with concentrated H₂SO₄: Cu + 2H₂SO₄ → CuSO₄ + SO₂↑ + 2H₂O; with dilute HNO₃: 3Cu + 8HNO₃ → 3Cu(NO₃)₂ + 2NO↑ + 4H₂O. Adding alkali to Cu²⁺ salts precipitates blue Cu(OH)₂: CuSO₄ + 2NaOH → Cu(OH)₂↓ + Na₂SO₄; on heating Cu(OH)₂ → CuO + H₂O. CuSO₄·5H₂O is blue vitriol, blue crystals; its mixture with lime (Bordeaux mixture) is used against plant pests and diseases. Copper is made into wires, bronze (Cu + Sn) and brass (Cu + Zn).
Collect information and draw pictures of copper objects (wire, coin, the green layer called patina): why does a copper statue turn green over time? Copper salts are poisonous: never put them in the mouth. Experiments with blue vitriol are done only by the teacher.