Investigate the reactions of group 2 elements
Less precipitate is formed down the group with increasing solubility. If you have any direct knowledge of this, preferably with a bit of video to support it, could you let me know via the address on the about this site page.
Group 2 elements reaction with water
Summary of the trend in reactivity The Group 2 metals become more reactive towards water as you go down the Group. That is what you would expect. Beryllium oxide isn't fully ionic. This is the energy needed to break the bonds holding the atoms together in the metallic lattice. However, nitrate ions are easily reduced to nitrogen monoxide and nitrogen dioxide. This leads to lower activation energies, and therefore faster reactions. Calcium, for example, reacts fairly vigorously and exothermically with cold water. The easier it is to lose the electrons the faster the element will be able to react. You will find a further link to a wider discussion of ionisation energy if you need it. The Magnesium reacts fiercely enough to melt into the glass. Colorless solutions of the metal nitrates are also formed. Less precipitate is formed down the group with increasing solubility. Beryllium has a strong resistant layer of oxide on its surface which lowers its reactivity at ordinary temperatures. Summarising the reason for the increase in reactivity as you go down the Group The reactions become easier as the energy needed to form positive ions falls. The graph shows the effect of these important energy-absorbing stages as you go down Group 2.
However, nitrate ions are easily reduced to nitrogen monoxide and nitrogen dioxide. However, the reaction is short-lived because the magnesium hydroxide formed is almost insoluble in water and forms a barrier on the magnesium preventing further reaction.
Beryllium and magnesium These are just like the reactions with dilute hydrochloric acid, and you have probably been familiar with the reaction between magnesium and dilute sulphuric acid almost since you started doing chemistry. Colorless solutions of the metal nitrates are also formed.
Similarly, if you calculate the enthalpy changes for the reactions between calcium, strontium or barium and cold water, you again find that the amount of heat evolved in each case is almost exactly the same - in this case, about kJ mol It uses these reactions to explore the trend in reactivity in Group 2.
For example: Calcium, strontium and barium Calcium sulphate is sparingly soluble, and you can think of strontium and barium sulphates as being insoluble. You'll have done this with Magnesium and Calcium - you can assume that the reactions with Ba and Sr will be more vigorous. Looking at the activation energies for the reactions The activation energy for a reaction is the minimum amount of energy which is needed in order for the reaction to take place.
These stages involve the input of: the atomization energy of the metal. The formation of the ions from the original metal involves various stages all of which require the input of energy - contributing to the activation energy of the reaction.
Group 2 reactions with chlorine
You can be asked to define the first ionisation energy but not any of the others. The second and third factors outweigh the first - say something like this in your answers. The formation of the ions from the original metal involves various stages all of which require the input of energy - contributing to the activation energy of the reaction. In the calcium case, you will get some hydrogen produced together with a white precipitate of calcium sulphate. Beryllium has a strong oxide layer rather like the more familiar aluminium which slows reactions down until it has been removed. Equation just like the magnesium one below. Summarising the reason for the increase in reactivity as you go down the Group The reactions become easier as the energy needed to form positive ions falls. Hydrogen gas is formed, along with colorless solutions of beryllium or magnesium sulfate. The explanation for the different reactivities must lie somewhere else.
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