1. PERIODIC TRENDS Coulomb’s Law Nuclear Charge Electron Shielding
Atomic Size
1st Ionization Energy
Electronegativity
Reactivity
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)

2. TRENDS Electron Shielding Remains Constant Nuclear Charge Increases
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)
Electron Shielding Increases
Nuclear Charge Increases

3. H Li Na 1s1 1s22s1 1s22s22p63s1 ATOMIC SIZE? 1 Hydrogen 3 Lithium 7 11
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding) 11 Na
Sodium 23
1s22s22p63s1

4. Atomic Size
As you go across a period atomic size decreases because the pull of the nucleus (nuclear charge) increases but electron shielding remains constant. The nucleus is able to pull the electrons closer (Coulomb’s law).
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding) 5 B
Boron 11 3 Li
Lithium 7 4 Be
Beryllium 9

5. Atomic Size Water sugar salt We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)

6. Atomic Size Water sugar salt We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)

7. TRENDS Atomic Size Decreases Electron Shielding Remains Constant
Nuclear Charge Increases
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)
Atomic Size Increase
Electron Shielding Increases
Nuclear Charge Increases

8. - 1st Ionization Energy +11
The energy required to remove the outermost electron from an atom.
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)

9. As you go down a group 1st ionization energy decreases.
Additional Electron shielding and increased distance from the nucleus makes removing the outermost electron much easier.
Increasing nuclear charge without any additional shielding makes removing the outermost electron more difficult.
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)
As you go across a period 1st ionization energy increases.

10. Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)

11. TRENDS 1st Ionization Energy Increases Atomic Size Decreases
Electron Shielding Remains Constant
Nuclear Charge Increases
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)
1st Ionization Energy Decreases
Atomic Size Increase
Electron Shielding Increases
Nuclear Charge Increases

12. Electronegativity -
+11
A measure of an atom or group of atom’s tendency to attract electrons
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)

13. As you go down a group Electronegativity decreases.
Additional Electron shielding and increased distance from the nucleus makes adding a new electron more difficult
Increasing nuclear charge (pull) without any additional shielding makes makes adding an electron easier.
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)
As you go across a period Electronegativity increases.

14. Fluorine is the most electronegative element.
What about the Noble gasses?
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)

15. TRENDS Electronegativity Increases 1st Ionization Energy Increases
Atomic Size Decreases
Electron Shielding Remains Constant
Nuclear Charge Increases
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)
1st Ionization Energy Decreases
Electronegativity decrease
Atomic Size Increase
Electron Shielding Increases
Nuclear Charge Increases

16. Reactivity
For now we can think of an atom’s tendency to lose or gain electrons as its reactivity.
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)
So atoms that lose electrons very easily or have a strong affinity for electrons are considered the most reactive.

17. Nonmetals: Reactivity Increases
Metals: Reactivity decreases
Electronegativity Increases
1st Ionization Energy Increases
Atomic Size Decreases
Electron Shielding Remains Constant
Nuclear Charge Increases
Nonmetals: Reactivity decreases
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)
1st Ionization Energy Decreases
Metals: Reactivity Increase
Electronegativity decreases
Atomic Size Increase
Electron Shielding Increases
Nuclear Charge Increases

18. Assignment
1st Ionization energy is the amount of energy needed to remove the outermost electron in an atom.
2nd Ionization Energy level is the energy required to remove the next electron.
QUESTION: Will sodium have a higher or lower 2nd Ionization energy compared to its first Ionization energy? Explain this in terms of the inverse square law, Coulomb’s law and electron shielding.
Water sugar salt
We are going to talk about bonding
Bonding between atoms is CIM
Why do 2h and OThere are several difference bond types in Chemistry.
All are concerned with electrons.
Intermolecular bonds occur between molecules (hydrogen bonding)
ESSAY QUIZ GRADE: Explain periodic trends in first ionization energy, electronegativity, atomic size and reactivity in terms of Coulomb's law, nuclear charge and electron shielding. BE THOROUGH!