![]() Gethin: So, the further down the table you go the more reactive they become. So, the reason we didn't see the reactions of those last three metals is that they are so reactive the explosion would be far too big. Miss Armit: No, it's the second rarest element on Earth. That's not an element that you hear a lot of. We saw there lithium, then sodium and then potassium, but you didn't see rubidium, caesium and francium. As you can see the metal's get increasingly more reactive as you go down this group. Gethin: It's fair to say that you love the Group 1 metals, don't you. Well, sodium is below lithium in group one and the reactivity of the alkali metals increases as you go down the group, so potassium is even more reactive. So let's try it with another Group 1 metal - sodium.Īs you can see it reacts far more vigorously then lithium. And can you see the little purple trail there? That universal indicator is showing us that the water now contains an alkali in this case - lithium hydroxide. It's transferring its energy to its surroundings by heating. This knowledge is vital for answering MCAT questions. By understanding trends in valence electrons on the periodic table, you can predict an elements behavior, reactivity, and interactions with other elements. Well, you can see it's reacting with the water straight away - it's steadily fizzing away there. The periodic table allows you to identify trends, such as atomic radius, ionization energy, electronegativity, and electron affinity. And if I put some universal indicator in, like this, you'll see that it's green and that means it's neutral.īut let's see what happens when we put the lithium in. Complete information about the Helium element - Atomic Number 2, atomic mass 4. Patterns and trends in the periodic table - Periodicity - Higher Chemistry Revision - BBC Bitesize Higher Periodicity Patterns and trends in the periodic table The periodic table arranges. And do you see how quickly it tarnishes, how quickly it's changing colour? Here we've got some water. Helium (He) element properties, information, facts, uses and Periodic Table trends. For elements with no stable isotopes, the mass number of the isotope with the longest half-life is in parentheses. These can be found in nature in both free and combined states. It consists of the elements oxygen, sulfur, selenium, tellurium and polonium. Here I've got some lithium and I'm just going to cut a little bit off. The oxygen family, also called the chalcogens, consists of the elements found in Group 16 of the periodic table and is considered among the main group elements. When a Group 1 element reacts with water it produces a metal hydroxides solution and hydrogen gas. They're soft and shiny when freshly cut, but they quickly tarnish as the metal reacts with oxygen in the air. Let's take a look at some Group 1 metals then - also known as alkaline metals.įran: Group 1 elements are called the alkali metals. Gethin: And today we're going to be looking at the periodic table.
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