Periodic Table Explained: Introduction

In the first video we saw that all things in the world are made of incredibly small particles called atoms and also that there are 92 different types of them, most things have more than one type of atom, but this nugget of pure gold contains only Gold atoms, that's why we call it an element, an element is a substance made from only one type of atom. As we zoom out, we see the gold atoms turn back into a piece of gold. If we move away from the silver atoms, we would see a piece of silver. Instead, because there are 92 types of atoms, there must be 92 elements, one for each type.

You've probably already heard of some of them, like carbon, iron, and aluminum, or aluminium, if you're American, but maybe not astatine or terbium, which has so many elements. There are many names to remember, fortunately there is a list that shows all the items. It starts with the element with the lightest atoms, hydrogen, and goes to the element with the heaviest elements, uranium. This list is called the

periodic

table

. How about you grab your own copy now and check it out while you watch the video. The lightest element, hydrogen, is at the top left of the

table

.

Each element can be written in shorthand using one or two letters called its symbol, which is capital H for hydrogen, not surprisingly each element also has its own number showing its place on this list, called its atomic number, hydrogen is the lightest element, so its atomic number is 1. If we zoom in on the helium at the top right, we can see that its symbol is h-e-b. Check it out to make it a little different, two hydrogens and its atomic number is two being the second lightest element the third lightest element is lithium so it has an atomic number of three where is lithium starts in the next row this row goes up up to atomic number ten before starting another row how many rows are one two three four five six seven the

periodic

table has seven horizontal rows what about these rows below called lanthanides and actinides?

Well, they actually belong to rows six and seven and should be placed in these spaces. Lanthanides are elements 5771 and actinides are elements 89 to 103 - place them we need to make the periodic table wider this full table is more accurate and some versions are printed this way this layout also makes it easier to see how many elements there are in each row 2 in the first row 8 in the second eight in the third 18 in the fourth 18 also in the fifth 32 and the sixth 32 and the seventh in total there are 118 elements hc' how come in the future airline 92 elements uranium being the last, yes, but intelligent?

Scientists have created artificial elements in the laboratory such as neptunium and plutonium. The items next door that were manufactured in 1940. These new items make the overall list of items a little longer. Let's collapse the periodic table to its usual form, which is more convenient to fit. On the screen you can see that the periodic table is also organized into vertical columns that scientists call groups. How many groups are there? One, two, three, four, five, six, seven, eight, nine, ten, eighteen, eighteen, vertical groups. The key point about groups is that they contain elements that are similar to each other as members of a family, for example all group 1 elements except hydrogen are soft, malleable metals that explode when you put them in water.

Some groups even have family names. Group 1 elements are called alkali metals. Group 2 elements are alkaline. The terrestrial metals of group 17 are halogens and group 18 are other noble gases. Now you are ready to read the periodic table, what is the name of the element with atomic number 30? Just scan and find 30 Zink, what is the atomic number of? calcium now you have to find calcium in table 20 which row is sulfur in the third row choose any element in the fifth row there are many possible answers for this it could be strontium tin iodine you choose which group is chlorine in group 17 choose an element in the Group 15 could be nitrogen or arsenic or any of the others, your choice, but what if you were asked which element is in row five and group two?

There can only be one answer, strontium, each element has its own unique row combination. and group, can you see the gray diagonal band that divides the periodic table into two parts? This divides the elements into metals on the left and non-metals on the right. What is a metal? Here are some titanium, iron, chromium, aluminum, silver and gold with the atomic numbers above. the symbols have you noticed that these metals are shiny and solid all are fine except liquid mercury the metals also conduct electricity and heat here the different metals are connected to an electrical circuit if the light bulb lights up it means that the thing is an electrical conductor They are all medals and are also malleable, meaning that if you build them with a hammer they will flatten into a thinner shape.

Here you can see that aluminum has three metallic properties, it has already been flattened into a thin sheet, it is shiny and it conducts electricity. I looked at aluminum, titanium, chrome, iron, silver and gold, all to the left of the diagonal, and saw that they all have metallic properties. What about the nonmetals on the right side of the diagonal? They are the opposite. Most non-metallic elements are liquids or gases, but there are some solids and these can be tested more easily here. Sulfur and selenium show that they do not conduct electricity. Can you see that the light bulb does not light up and if you hit this coal with a hammer it breaks into pieces?

This is called being brittle, it is the opposite of being malleable, let's use the periodic table to predict if an element would be a metal or a non-metal, how about osmium with atomic number 76? Osmium is to the left of the diagonal gray band, so it should be a metal, how about iodine? that's to the right of the diagonal line, so it's a nonmetal, let's try something complicated. Oh, do you think yttrium with atomic number 39 would be shiny? It's to the left of the diagonal line, so it's a metal, so it's probably shiny. Would phosphorus with atomic number 15 conduct electricity? hmm, it's to the right of the diagonal, so it's a non-metal, probably not.

What happens to the elements inside the diagonal band? Let's take a look at silicon, it looks shiny like a metal, but if you hit it with a hammer it breaks into pieces, making it brittle. a non-metal and the dull glow of the light bulb tells us that it conducts electricity more than a non-metal but not as much as a metal and this gives it the name semiconductor. These elements are also called semimetals because they have properties that are between metals and non-metals are more metals or non-metallic elements metals almost three quarters of the elements in the periodic table are metals but that does not mean that they are more abundant because in the Earth's crust there are more oxygen and silicon atoms than the rest combined and the universe as a whole is mainly hydrogen, in fact hydrogen is special in many ways, it is to the left of the diagonal, but it is not a metal, well, it can't be, it is a gas, it seems that it is in the Group one as a member of the alkali metals but it cannot be because it is not a metal the truth is that hydrogen does not belong to any group and is considered a group on its own some periodic tables even put it just to show this just remember hydrogen It's special the periodic table compresses a lot of information into a small space the English writer CP Snow said that the periodic table took all the jumbled data about the elements and fit it into a pattern and, from my point of view, it was like turning a jungle into a garden. is that the periodic table is the alphabet of the universe, while our ordinary alphabet is a list of letters that can form all the words in our language, the periodic table is a list of elements that can form all the substances in the universe.