Calcium - Periodic Table of Videos

Calcium is the third element in group two of the

periodic

table

. It's actually very common. We find it all over the world in all types of minerals. So, for example, you can have bones, this is the pelvis of a sheep, I found it while I was walking one day, you can see the legs coming in here and there. Here we have some

calcium

chips. We keep them in our glove compartment. This glove box here is a nitrogen filled contraption, it's dry nitrogen so we can keep our

calcium

away from oxygen and also moisture, because obviously what we don't want is that when we have our nice very reactive calcium surface, we don't want it to get Tarnish due to oxides too quickly before we can react with things.

So what we have here inside the bottle are calcium shavings. Calcium is quite hard compared to the heavier group two elements, i.e. strontium and barium, so it is more difficult to file. Bones are also made of calcium phosphate mixed with some organic material and are very strong due to the structure within the bones. There are all types of mollusk shells and the like in which they use calcium carbonate from seawater, extracting the calcium, reacting with carbon dioxide and forming their shells. And since shells are made of calcium carbonate, which dissolves in acid, people are quite concerned about the effects of global warming.

It's not warming, but when CO2 dissolves in the sea it makes it more acidic, so in principle the shells could start to dissolve and some mollusks might not survive because they simply can't make them. If I just pour them out so you can see. Calcium appears more metallic than metallic calcium itself because of the way the electrons behave in the solid. In fact it is because it is a very good electrical conductor but the compounds are all white, because calcium does not have free electrons that can pass from one energy level to another as can be said of copper.

So, copper sulfate is a beautiful blue color, calcium sulfate is white and is actually colorless, so if you see a big crystal of calcium sulfate, it looks like glass. But the white is caused by very small crystals that scatter light, in the same way that any type of white powder scatters light, flour for example, talcum powder or something like that. The calcium compounds themselves are actually mostly white, but the calcium metal itself, as you can see, has tarnished parts, but there are also some shiny parts where it is not tarnished. So you're actually also seeing the metal, the shine of the metal there.

Calcium carbonate dissolves in CO2-saturated water to produce calcium bicarbonate, which is more soluble. And so you can obtain water, the so-called hard water, which has quite high levels of calcium. And when this seeps through the soil and into a cave, it can crystallize and left hanging pillars of calcium carbonate, which are called stalactites. And you can have pillars growing from the ground called stalagmites. This is a stalagmite from Türkiye. One of my friends called Hugh was very naughty. He knew I was interested in minerals and he took it out of a cave in Turkey about 45 years ago, he brought it back and gave it to me, so I was very pleased.

And you can see that the outside looks quite stained, and on the inside you can see nice calcium carbonate crystals because it has grown very, very slowly and so it can crystallize. And sometimes these stalagmites and stalactites can grow very large. And more recently, in recent years, huge crystals of calcium sulfate have been found underground. Some of you may have seen photographs of caves in Mexico where there are crystals large enough to walk along. So there is no danger that calcium will ever run out, it is the base of cements and concrete, or one of the bases because then other elements such as iron and silica are needed to make the concrete itself, but calcium is one of the main components.

We'll take calcium chloride, put it on the fire, and do a flame test to see if we can see the color of the calcium in the flame. As I said before about calcium compounds, calcium compounds are often white, and here is a white calcium compound. So I'm going to put it on the fire and see if it takes on any color. Hello, it looks quite red, doesn't it? Brick red is the classic calcium color. It's a little orange to me, there might be a little sodium or something. That was our calcium flame test. The reason you don't find chunks of calcium metal lying around, like you do with copper or gold, is that calcium metal is very reactive, it reacts with water very quickly.

Magnesium does not react because it has an oxide layer on the surface, so surprisingly, magnesium is not as reactive as calcium. You can use magnesium, or its alloys, for the wheels of your car, they spin very quickly because they are light. You couldn't have calcium tires on your car, well, yes, but the first time it rained your whole car caught fire. Again, what we have is our calcium chloride, hydrated calcium chloride. We have a lot on this spatula. I will put it in the flame so you can see that it burns with a brick red flame that is characteristic of calcium.

Actually, it's a little orange to me too, there might be a little sodium or something. Do you have more there? A bit. Many people see calcium as a very English element, unlike strontium, which was discovered in Scotland, due to the white cliffs of Dover, the gateway for many people when they first arrive in England. They are made of calcium carbonate. And so this white color of chalk is very characteristic and throughout the southern part of England you find large quantities of chalk, which in the north of England tends to be limestone, which is also calcium carbonate but a slightly different variety of calcium carbonate. then it is a yellow or honey color due to the impurities of iron or some other element it contains.

Well, you need calcium for all kinds of processes in the body and, of course, to strengthen your bones. Particularly, say in the case of pregnant women, they need calcium for the bones of the developing baby. But as people age, calcium can leach out of their bones and make them very brittle, which is why older people sometimes break their hips and bones so easily. Therefore, drinking milk and eating other sources of calcium is good because it helps replenish bones and maintain a reasonable level of calcium.