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The Periodic Table

Group 1 - The Alkali MetalsGroup Trends.

What are the Group Trends for the Alkali Metals?

As you go down group 1 from lithium to francium,
the alkali metals

1. Have lower melting points and boiling points.

2. Are softer.       3. Have a higher density.

4. Have bigger atoms. Each successive element in the
next period down has an extra electron shell. It is the
electron shells which take up nearly all the space of an atom.

5. Are more reactive. As the size of the atoms increase,
the outer electron (which it wants to lose to become a stable ion)
is further and further from the positive nucleus. It is the attraction
between the negative outer electron and the positive nucleus
which determines how easily the electron will be lost. The bigger
the atom, the further away the outer electron is, the more
easily the outer electron is lost, and the more reactive the metal is.

Also, the inner electrons (being negatively charged) protect the
outer electron from the full attraction of the positive nucleus.
The outer electron is said to be shielded by the inner electrons.
The more electron shells there are, the greater the shielding.

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