Wednesday, 1 May 2013

2.6 describe the reactions of these elements with water and understand that the reactions provide a basis for their recognition as a family of elements

The group one elements- lithium, sodium, potassium- are easily identifiable as the same group due to the fact that they all react vigorously with water (clearly due to the fact they have similar electronic configurations.)

The reactions that occur are huge- they get bigger further down the group. Hydrogen gas is produced as well as metal hydroxide.

Search on youtube; there are plenty of videos of there reactions.

6 comments:

  1. Thanks for the info, just saying though that you should probably describe the reactions (e.g. fizzes, floats, moves around, melts into a ball if it's sodium or potassium and gradually disappears): http://www.chemguide.co.uk/inorganic/group1/reacth2o.html

    ^ top of page gives information on this topic.

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    1. same here. you dont really say too much, but thanks anyway

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  2. Lithium
    When lithium is added to water, it floats. It fizzes steadily and becomes smaller, until it eventually disappears.
    lithium + water → lithium hydroxide + hydrogen
    2Li(s) + 2H2O(l) → 2LiOH(aq) + H2(g)

    Sodium
    When sodium is added to water, it melts to form a ball that moves around on the surface. It fizzes rapidly, and the hydrogen produced may burn with an orange flame before the sodium disappears.
    sodium + water → sodium hydroxide + hydrogen
    2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

    Potassium
    When potassium is added to water, the metal melts and floats. It moves around very quickly on the surface of the water. The hydrogen ignites instantly. The metal is also set on fire, with sparks and a lilac flame. There is sometimes a small explosion at the end of the reaction.
    potassium + water → potassium hydroxide + hydrogen
    2K(s) + 2H2O(l) → 2KOH(aq) + H2(g)

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    1. thank you!! extremely useful. i remember learning this in class! :)

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