1. The Periodic Table Trends
Chapter 6

2. Section 6.3: Periodic Trends
The electron cloud surrounding the nucleus is based on the probability and does not have a clearly defined edge
Atomic size is defined by how closely an atoms lies to a neighboring atom

3. Atomic Radii Trend Trends within periods Trends within groups
Generally decreases as you move left-to-right across a period (row)
Trends within groups
Generally increases as you move down a group

4. Ionic Radius
An ion is an atom or a bonded group of atoms that has a positive or negative charge
When atoms lose electrons and form positively charged ions, they always become smaller
When atoms gain electrons and form negatively charged ions, they always become larger

5. Lose Electrons  Smaller ionic radii
Gain Electrons  larger ionic radii

6. Ionization Energy (I.E.)
Ionization Energy- the energy required to remove an electron from a gaseous atom
1st Ionization Energy- removes the 1st electron
2nd Ionization Energy- removes the 2nd electron… and so forth
I.E. is an indication on how strongly an atom’s nucleus holds onto its valence electrons

7. Octet Rule- atoms tend to gain, lose or share electrons in order to acquire a full set of eight valence electrons

8. Octet Rule- atoms tend to gain, lose or share electrons in order to acquire a full set of eight valence electrons
Hydrogen and Helium are exceptions (they’ll be happy with 2 V.E.)
Determines the types of ions likely to form
Elements on the right side tend to gain electrons
Elements on the left side tend to lose electrons

9. Electronegativity
Indicates the relative ability of its atoms to attract electrons in a chemical bond
Noble gases form very few compounds so they are left out
In a chemical bond, the atom with the greater electronegativity more strongly attracts the bond’s electrons

11. In Summary Atomic radius decreases Ionization energy increases
Electronegativity increases
Ionization energy decreases
Electronegativity decreases
Atomic radius increases 1A 2A 3A 4A 5A 6A 7A