![]() It takes more energy to break these.Įven allowing for other factors (like the energy released when the positive ions form attractions with water in the solution formed), the net effect of this is that reactions involving magnesium oxide will always be less exothermic than those of sodium oxide. In the magnesium oxide case, the attractions are between 2+ and 2. In the sodium oxide case, the solid is held together by attractions between 1+ and 2- ions. However, it isn't as strongly basic as sodium oxide because the oxide ions aren't so free. Magnesium oxide is again a simple basic oxide, because it also contains oxide ions. For example, it would react with dilute hydrochloric acid to produce sodium chloride solution. Depending on its concentration, this will have a pH around 14.Īs a strong base, sodium oxide also reacts with acids. Sodium oxide reacts exothermically with cold water to produce sodium hydroxide solution. It is basic because it contains the oxide ion, O 2-, which is a very strong base with a high tendency to combine with hydrogen ions. Sodium oxide is a simple strongly basic oxide. ![]() If you are working towards a UK-based exam (A level or its equivalent) and haven't got any of these things follow this link before you go any further to find out how to get them. It is essential to know what your syllabus says about this topic, and to explore past papers and mark schemes - otherwise you are going to end up bogged down in a mass of detail that you don't actually need to know about. Don't lose sight of the overall trend in the period with respect to the highest oxides when you are looking at all this detail. Warning: The rest of this page contains quite a lot of detail about the various oxides. These reactions are all explored in detail on the rest of this page. ![]() They will, however, all react with bases such as sodium hydroxide to form salts such as sodium sulphate. The pattern isn't so simple if you include the other oxides as well.įor the non-metal oxides, their acidity is usually thought of in terms of the acidic solutions formed when they react with water - for example, sulphur trioxide reacting to give sulphuric acid. Those are the ones on the top row above, and are where the element is in its highest possible oxidation state. ![]() An amphoteric oxide is one which shows both acidic and basic properties.įor this simple trend, you have to be looking only at the highest oxides of the individual elements. The trend is from strongly basic oxides on the left-hand side to strongly acidic ones on the right, via an amphoteric oxide (aluminium oxide) in the middle. The trend in acid-base behaviour is shown in various reactions, but as a simple summary: Use the BACK button on your browser to return quickly to this page later if you choose to follow this link. Note: If you haven't already been there, you might be interested in looking at the page about the structures and physical properties of the Period 3 oxides as a useful introduction before you go any further. The oxides we'll be looking at are: Na 2O Argon is obviously omitted because it doesn't form an oxide. This page looks at the reactions of the oxides of Period 3 elements (sodium to chlorine) with water, and with acids or bases where relevant. Acid-base behaviour of the period 3 oxidesĪCID-BASE BEHAVIOUR OF THE PERIOD 3 OXIDES
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