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The Group 1 metal (M) is oxidised to its metal ions, and water is reduced to hydrogen gas (H 2) and hydroxide ion (OH −), giving a general equation of: 2 M(s) + 2 H 2 O(l) 2 M + (aq) + 2 OH − (aq) + H 2 (g) [8] The Group 1 metals or alkali metals become more reactive as their number of energy levels inceases.
The order of reactivity, as shown by the vigour of the reaction with water or the speed at which the metal surface tarnishes in air, appears to be Cs > K > Na > Li > alkaline earth metals, i.e., alkali metals > alkaline earth metals, the same as the reverse order of the (gas-phase) ionization energies.
Metal aqua ions are often involved in the formation of complexes. The reaction may be written as pM x+ (aq) + qL y− → [M p L q] (px-qy)+ In reality this is a substitution reaction in which one or more water molecules from the first hydration shell of the metal ion are replaced by ligands, L. The complex is described as an inner-sphere complex.
Solvated electrons are involved in the reaction of alkali metals with water, even though the solvated electron has only a fleeting existence. [10] Below pH = 9.6 the hydrated electron reacts with the hydronium ion giving atomic hydrogen, which in turn can react with the hydrated electron giving hydroxide ion and usual molecular hydrogen H 2. [11]
In fact, the rate of reaction of alkali metals (as evidenced by their reaction with water for example) is a function not only of position within the group but also of particle size. Hydrogen does not react with oxygen—even though the equilibrium constant is very large—unless a flame initiates the radical reaction, which leads to an explosion.
NaK containing 40% to 90% potassium by mass is liquid at room temperature.The eutectic mixture consists of 77% potassium and 23% sodium by mass (NaK-77), and it is a liquid from −12.6 to 785 °C (9.3 to 1,445.0 °F), and has a density of 0.866 g/cm 3 at 21 °C (70 °F) and 0.855 g/cm 3 at 100 °C (212 °F), making it less dense than water. [3]
This secondary hydrogen gas explosion produces the visible flame above the bowl of water, lake or other body of water, not the initial reaction of the metal with water (which tends to happen mostly under water). [74] The alkali metal hydroxides are the most basic known hydroxides. [10]: 87 Recent research has suggested that the explosive ...
A mnemonic is a memory aid used to improve long-term memory and make the process of consolidation easier. Many chemistry aspects, rules, names of compounds, sequences of elements, their reactivity, etc., can be easily and efficiently memorized with the help of mnemonics.