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Periodic Trends

PostPosted: April 16th, 2011, 4:54 pm
by Jessica
Ionization energy: the energy required to remove an electron from an atom

The lower the ionization energy, the easier to remove electrons

I.E. increases left to right across a period and bottom to top. There are exceptions. Elements whose sublevels are half filled or filled are hard to remove, therefore their I.E. are high.

For example, it would be easy to remove electrons from Silicon. When you get to Phosphorous, the I.E. has a huge increase because its ending notation is 3p[super]3[/super], and the p sublevel is half filled, therefore making it stable. It would not want to lose electrons.


Electronegativity: the ability of an atom to attract atoms to itself in a bond

The trend is the same as ionization energy. Basically electronegativity is a rating system. Francium's electronegativity is 0.7, the lowest, and Fluorine has the highest, with 4.0


Atomic radii - the trend is the opposite of I.E. and electronegativity. It decreases from bottom to top and left to right. In other words, it INCREASES from top to bottom and right to left.

Positive ions are always smaller than their neutral atoms, and negative ions are always larger than their neutral atoms.