1. Periodic Trends-Patterns on the periodic table

3. ELECTRONEGATIVITY
Electronegativity is the ability of an atom to attract electrons when they are chemically combined with other atoms..
Trend: Fluorine (F) has the highest electronegativity. As an element gets closer to F, the higher it’s electronegativity.

4. The Atomic Radius of an atom is defined as ½ the distance between the nuclei of two chemically bonded atoms of the same element.

5. s & p-block atomic radii

6. Atomic Radius decreases to the right?
As atomic # increases, the + charge in the nucleus also increases.
So does the number of – charges.
From Coulomb’s Law
F = Kq1q2 r
Effective Nuclear Charge(Zeff.)-force of attraction between p+ & e- is called the Zeff.

7. Sizes of Ions Related to Positions of the Elements in the Periodic Table

8. Atomic Radius
The closer the element symbol is to francium, the larger it’s radius.
This is only a trend.
This trend only applies if all atoms have
the same charge.

9. Ionic Radius Ion – any atom with an overall charge.
If the charge is positive(+), the ion is called a cation.
If the charge is negative(-), the ion is called an anion.
Ionic Radius Rule = the more negative an ion the larger it’s radius.

10. Arrange each group by increasing radius:
1) Ge, S, Ca, Ga, Rb, He, F
Ans: He, F, S, Ge, Ga, Ca, Rb
2) Al, Al3+, Ca, Ca2+, P, P3-, N3-, Sr, O2-
Ans: Al3+, Ca2+, P, Al, Ca, Sr, O2-, N3-, P3-

11. Electron Affinity (electron loving)
Electron Affinity- the energy change associated when an atom, in the gaseous state gains an electron.
Trend: same as electronegativity

12. Shielding Effect
Shielding Effect- the interference of the ability of the nucleus to attract its valence electrons, by lower level electrons (core electrons)
Shielding effect increases down a group.
Shielding effect along with electronegativity determine atomic radius of an atom.

13. First Ionization Energy
First Ionization Energy – The energy required to remove the first electron from a neutral atom, in the gaseous state.
Trend: He has the highest!

14. Oxidation Number- an assigned charge, not always a true charge.

15. Common oxidation numbers
Alkali Metals & Ag: +1
Alkaline Earth Metals & Zn & Cd: +2
Group 13: +3
Group 14: +4 or -4
Group 15: -3
Group 16: -2
Group 17: -1
Group 18: 0