Alkali Metals Flashcards
What happens when they react with water?
Hydrogen gas is given off and metal hydroxide is produced. The speed and violence of the reaction increases as you go down the group.
Why are they kept under oil?
They are very reactive, and need to be kept away from air and water. They form alkaline solutions when mixed with water.
Why do group one elements all have similar properties?
It is because of electronic structure, they all have one electron.
What sort of charge do they form?
They form a ion with a single positive charge, as they lose on electron on the outer shell. e.g. Na => Na+ + x- . The ions are now stable.
Why does the reactivity increase as you go down the group?
The atoms get larger and the outer electron gets further away from the nucleus, so the attraction between the outer electron and the nucleus weakens.
How does lithium react with water?
It fizzes steadily and gets smaller until it disappears.
How does sodium react with water?
It fizzes violently, and may have an orange flame, then it dissapears
How does potassium react with water?
It moves around very quickly on the surface of the water. The hydrogen ignites instantly. The metal is also set on fire, with a lilac flame. There is sometimes a small explosion at the end of the reaction.
