Introduction To Mercury, Hg. Mercury is a chemical element with the symbol Hg. It has 80 number of Proton, and 1 mole of itcontains 201 gram of Mercury. It is located in the period 6 group 12. The electron configuration forMercury is [Xe] 4f145d106s2. Figure 1 : The Electron Configuration of Mercury. Mercury atoms have higher tendency to become a positively charge ion, cation, with an oxidationnumber of +2, to achieve a stable octet electron configuration. Hg -> Hg2+ + 2e However in certain cases, Mercury can also release one electron due to sharing electron withother atoms to produce another compound. For example in, Mercuric Chloride Hg2Cl. The oxidationnumber of Mercury is +1.The ionization energy pattern in Mercury The ionization energy is the energy required to remove the most loosely held electronfrom one mole of gaseous atoms to produce 1 mole of gaseous ions. The ionization energies ofmercury are given below. Ionization energy number Enthalpy /kJ mol-1 1st 1007.1 2nd 1810 3rd 3300 Table 1: The relationship between ionization energy number with enthalpy
Enthalpy vs Ionization Energy Number 3500 3000 2500 2000 Enthalpy vs Ionization 1500 Energy Number 1000 500 0 1 2 3Physical Properties of Mercury. Mercury, which is also known as Quicksilver, has a freezing point of −38.83 °C and a boilingpoint at 356.73 °C. It is clearly shows that Mercury will be in the form of liquid in standard temperatureand pressure, s.t.p. (1 atm, 1 °C) . Mercury is a heavy, silvery-white metal. As compared to other metals,it is a poor conductor of heat, but a fair conductor of electricity. Figure 2 : Liquid MercuryMercury has two physical properties of special interest. First, it has very high surface tension.Surface tension is a property of liquids that make them act like they are covered with a skin. For
example, some water bugs are able to walk on the surface of water. With care, one can float aneedle on the surface of water. These incidents are possible because of waters surface tension.Secondly, Mercury is also a very good conductor of electricity. This property is used in a numberof practical devices. One such device is a mercury switch, such as the kind that turns lights onand off. A small amount of mercury can be placed into a tiny glass capsule. The capsule can bemade to tip back and forth. As it tips, the mercury flows from one end to the other. At one end ofthe capsule, the mercury may allow an electric current to flow through a circuit. At the other end,no mercury is present, so no current can flow. Mercury switches are easy to make and veryefficient . Figure 2 : Mercury Switch The type of bond that we can found in Mercury is Metallic Bond. Usually most of the metal will have a metallic bond. For example like Sodium (Na), Magnesium (Mg) and Aluminum (Al). But what is Metallic bond? Why is that most metal will have these kind of bond? Precisely, Metallic Bond is thechemical bonding that holds the atoms of a metal together. Metallic bonds are formed from the attractionbetween mobile electrons and fixed, positively charged metallic atoms. Whereas most chemical bonds are localized between specific neighboring atoms, metallic bonds extend over the entire molecular structureChemical Properties of Mercury. i. Formation of Insoluble Salt. Insoluble salt can be prepared by double decomposition method. Double decomposition method involved the addition of one soluble salt solution with another one soluble salt. Soluble salt + Soluble salt -> insoluble salt + soluble salt.
One of the insoluble salt that we can produce is Mercury (II) Chloride. This orange precipitate, HgCl2 , is highly toxic. Firstly we need to prepare 0.5 M sodium iodide (very pale yellow) and 0.1 M mercury(II) chloride (colorless). Pour 0.1 M mercury(II) chloride (colorless) into a test tube, followed by 0.5 M sodium iodide.ii. Reaction of mercury with airMercury metal reacts in air at about 350°C to form Mercury(II) oxide. 2Hg(s) + O2(g) → 2HgO(s) [red]iii. Reaction of mercury with waterMercury does not react with water under normal conditions. Hg + H2O → no observable changes.iv. Reaction of mercury with the halogensMercury metal reacts with fluorine, F2, chlorine, Cl2, bromine, Br2, or iodine, I2, to form thedihalides mercury(II) fluoride, HgF2, mercury(II) chloride, HgCl2, mercury(II) bromide, HgBr2,or mercury(II) iodide, HgI2, respectively. Hg(l) + F2(g) → HgF2(s) [white] Hg(l) + Cl2(g) → HgCl2(s) [white] Hg(l) + Br2(l) → HgBr2(s) [white] Hg(l) + I2(s) → HgI2(s) [red]v. Reaction of mercury with acidsMercury does not react with non-oxidizing acids but does react with concentrated nitric acid,HNO3, or concentrated sulphuric acid, H2SO4, to form mercury(II) compounds together withnitrogen or sulphur oxides.Mercury dissolves slowly in dilute nitric acid to form mercury(I) nitrate, mercurous nitrate,Hg2(NO3)2.vi.Organic mercury: Mercury can also combine with organic groups such as methylgroups to form organic mercury. The most common compound of this type is methylmercury, which is somewhat soluble in water, bio-available and highly toxic.