Reactions of the other metals in the Reactivity Series I offer this just as a bonus - not for you to remember! They are presented by Sir Martyn Poliakoff who is a research professor at the university. It comes from a wonderful collection of short videos about the elements in the Periodic Table from the University of Nottingham. I came across this reaction which I had never seen before (and would never have thought of trying) while I was searching for good videos for this page. The black product is a mixture of boron and silicon - you don't need to remember this! What happens is that the magnesium reacts with the glass as well as the steam. This bit of video avoids this problem by stopping it before you get to notice this! You would expect white magnesium oxide to be formed, but the tube usually shows a lot of black product as well as white. The magnesium is heated until it just starts to react, and then the heat is moved to produce a lot of steam. At the bottom of the tube is a wad of mineral wool soaked in water. The next bit of video shows a boiling tube with a coil of magnesium ribbon in it. That also applies to the other metals that we will need to react with steam. You get magnesium oxide produced rather than magnesium hydroxide at these higher temperatures. Magnesium will, however, burn in steam to produce magnesium oxide and hydrogen. If you put a small, but very clean, coil of magnesium in water and leave it for half-an-hour or so, bubbles of hydrogen do form on the surface and will often float the magnesium to the surface. What happens with the magnesium is that a small initial reaction coats the surface of it with a very thin layer of insoluble magnesium hydroxide, and that stops further water getting at the magnesium. Notice that there doesn't seem to be any reaction with the magnesium. It just shows four test tubes with each of the metals in water.Ĭoncentrate on the first two tubes which contain magnesium and calcium. Magnesium and calcium are at the top of Group 2 of the Periodic Table, and there is also a very, very short piece of video comparing the reactions of water of magnesium, calcium, strontium and barium (two other member of Group 2). You should also notice that the calcium moves around in the beaker, carried by the bubbles of hydrogen. This isn't very soluble in water and a lot of it is formed as a solid. The cloudiness is due to the formation of calcium hydroxide. You can see bubbles of hydrogen being produced. The first bit of video shows quite a large chunk of calcium being dropped into water. It looks a bit different because calcium is denser than water and so sinks. The reactions of calcium and magnesium with waterĬalcium's reaction with water is similar to lithium's. This also applies to the reaction of calcium with water and to magnesium's very slight reaction with cold water (below). The oxides of these metals all react with water to produce a hydroxide and so that is what you end up with. Note: You may wonder why you get a metal hydroxide formed rather than an oxide. This is the metal hydroxide formed dissolving in the water. If you watch the video again, in the relatively peaceful reactions, you will see a white trail under the metals as they move around. In each case, you get hydrogen produced and a solution of the metal hydroxide. For reasons that will become obvious, you won't usually come across rubidium and caesium in the lab. So, in this bit of video from the Open University they are starting with lithium at the top of the group, and then working down. As you will find later in the course, the reactivity of these metals increases the further down the group you go. If you looked at a copy of the Periodic Table you would find these metals at the top of Group 1. The reactions of potassium, sodium and lithium at the top of the series We will start by looking at the reactions of the metals at the top of the reactivity series. There are a couple of cases like that, and we will talk about them individually. Note: I say "in principle" because sometimes a metal that you might expect to react with water or steam doesn't, or only reacts much more slowly than you might expect. Metals below hydrogen won't be able to react with water in this way. If a metal is above hydrogen in the reactivity series it should, in principle, be able to remove the oxygen from the water to leave hydrogen gas. We haven't so far mentioned the position of hydrogen in the reactivity series, but it is really important for this topic and the next. The position of hydrogen in the reactivity series most reactive This page explores the way the position of a metal in the reactivity series affects its reaction with water or steam. The reactions between metals and water or steam Reactions between metals and water or steam
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