Valence Electrons & Periodic Trends

The outermost electrons, or the electrons in the highest occupied shell, are called…and determine how an element combines with other elements.

valence electrons

The number of electrons in the outermost level is the…

Valence number

Elements want to have a full outer shell, elements in groups 1-2 (something 13) do this by…

giving away electrons to become positive ions

Elements want to have a full outer shell, elements in groups 16-17 (something 15) do this by…

accepting electrons to become negative ions

Elements in the same group have similar chemical properties because…

They have the same valence shell electron configuration 

The elements in a row show a gradual change in chemical properties because...

their valence shell electron configuration changes gradually along the row.

There are main trends in the periodic table:

∙Atomic radius

∙Electronegativity

∙Ionization energy

∙Metallic Character

atomic radius generally…as you move from left to right across a period

decreases

atomic radius generally…as you move down a group

increases

The ionization energy is the…required to remove an electron from an atom.  

amount of energy

Removing an electron creates a…

positively charged ion, a cation.

Ionization energy… when moving down the periodic table

decreases

Ionization energy…when moving to the right across the periodic table

increases

It requires…energy to remove each successive electron.

more

…is the ability of an atom to attract other electrons.

Electronegativity

Electronegativity…when moving from the top to the bottom of the periodic table.

decreases

Electronegativity…when moving from left to right across the periodic table

increases

The exception to electronegativity are..

Noble gases

Noble gases neither want nor want to get rid of electrons because…

they have a full shell and they are stable

Gaining or losing an electron would … the stability of a noble gas atom.

decrease

…do not attract electrons, so are not electronegative

Noble gases