Periodic properties of the elements

25. Explore tendencies in the periodic table 

Watch the reaction of lithium, sodium or potassium with water.

Transcription:

Now let's see another reaction of the alkali metals, the reaction with water.

We'll start with Lithium. The metal floats on the water and reacts with it, giving off Hydrogen gas.

Now for Sodium, the same sort of thing happens, although the reaction is a bit more vigorous. All the alkali metals react with water in the same way.

Now for Potassium. This time you'll see a flame. The heat given out by the reaction is produced so quickly that the Hydrogen gas catches fire, it burns with a lilac flame.

The next element is Rubidium. This time we've put a safety screen between us and the reaction.You can see that things gradually become more terrifying as we go down the group.

Let's try Caesium, our 5th alkali metal. [Huge explosion]

Write a paragraph describing the reaction you have seen using the "heads and tails" in the "test 25"

     Elements in the same group in the periodic table have similar chemical properties. This is because their atoms have the same number of electrons in the highest occupied energy level. The alkali metals are the elements Lithium, Sodium, Potassium, Rubidium, Caesium and Francium. They are grouped together because they all behave similarly (except with different ferocity) and together form Group 1 of the Periodic Table.

26. Alkaline metals

Complete the "test 26" choosing the terms among those listed.

27.Working on language: making the opposite with the prefixes UN-, IN-, IL-and IM-

In many scientific words, the opposite is made by adding a prefix UN-, IN-, IL-and IM- to the terms.

Using Internet or the dictionaries on the right side of the screen, complete the following table as shown in the examples, inserting the correct term in the appropriate column.

28. The opposite of physical and chemical properties of the elements

Complete the following table writing the opposite of the terms listed.

Now, we are going to focus on other groups of elements. Let's go to the new tab called: "Groups in the periodic table"