Periodic Trends Learning the periodic table

Three major trend seen in the periodic table

• Radius of the atom– Distance between the nucleus

and outermost electrons

• Ionization energy– Energy needed to remove

outer most electrons

• Electron Affinity– Change in energy with

addition of elections

Atomic Radius• As the number of

protons increases the pull on the electrons increase, which decreases the size of the atom.

• As the number of shells increase, the size of the atom increases

Ionization Energy

Ionization Energy

• The farther the electron is from the nucleus,

• The easier it is to remove the electron.

• Larger atoms lose electrons more easily than smaller atoms.

Electron Affinity

Electron Affinity

• Electron affinity is based on the atoms’ ability to attract additional electrons.

• Why do atoms attract additional electrons?

• To complete the octet!

Electron Affinity is related to Electro Negativity

Electro negativity

• Is the ability to attract electrons.

• Fluorine has the highest electro negativity.

• The closer the element to Fluorine, the higher the electro negativity.

• Top number is the Atomic Number. It is the number of protons which equals the number of electrons

• The bottom number is the Atomic Mass. The average number of Protons and Neutrons in an element.

What are Valence Electrons??

They are the outer most electrons

On the periodic table :

These are models:

• What is a model?• A person’s interpretation

of observed events.• They are not what is

actually occurring.

A more accurate model

• The orbital model