(NR) Oct. 28, 2010: Trends on the Periodic Table

- Elements close to each other on the periodic table display similar characteristics.
- There are SEVEN important periodic trends:
1) Reactivity
2) Ion Charge
3) Melting point
4) Atomic Radius
5) Ionization Energy
6) Electronegativity
7) Density*

REACTIVITY:
- metals and non-metals show different trends.
- the most reactive metal is Francium; the most reactive non-metal is fluorine.

ION CHARGE:
- Elements ion charges depend on their group (column).

MELTING POINT:
- elements in the center of the table of the highest melting point.
- noble gases have the lowest melting points.
- starting from the left to right, melting point increases (until the middle)
> carbonis an exception!

ATOMIC RADIUS:
- radius decreases to the up and the right.
- helium has the smallest atomic radius.
- Francium has the largest atomic radius.

IONIZATION ENERGY:
- ionization energy is the energy needed to completely remove an electron from an atom.
- it increases going up and to the right.
- all noble gases have high ionization energy.
- helium has the highest ionization energy.
- francium has the lowest ionization energy.
- opposite trend from atomic radius.

ELECTRONEGATIVITY:
- refers to how much atoms want to gain elections.
- same trend as ionization energy.