1. Periodic Table Revisited
Chapter 14:
Periodic Table Revisited

2. Classifying the Elements by Configuration: Chapter 14.1
1. The noble gases:
Inert gases
Outmost s and p sublevels are filled.
Example:
Helium: 1s2
Neon: 2s2, 2p6

3. Classifying the Elements by Configuration: Chapter 14.1
2. The Representative Elements:
Outermost s and p sublevels are only partially filled.
Group A elements
Examples:
1A: alkali metals
2A: alkaline earth metals
7A: Halogens
Group # equals outermost electrons

4. Classifying the Elements by Configuration: Chapter 14.1
Examples:
Group 1A:
Na: 1s2, 2s2, 2p6, 3s1
Group 2A:
Mg: 1s2, 2s2, 2p6, 3s2
Group 7A:
F: 1s2, 2s2, 2p5

5. Classifying the Elements by Configuration: Chapter 14.1
3. Transition Metals:
Metallic elements where s sublevel and d sublevel contain electrons.
Group B elements
4. Inner Transition Metals:
Metallic elements where outermost s and f sublevels contain electrons.

6. Periodic Trends: Chapter 14.2
1. Atomic Radius
One half the distance between the nuclei of two like atoms in a diatomic molecule.
Group Trend:
Generally increases as you move down a group
Periodic Trend:
Decreases as you move from left to right.

7. Atomic radius vs. Atomic number

8. Periodic Trends: Chapter 14.2
2. Ionization Energy: The energy needed to remove an electron from a gaseous atom.
Group Trend:
Energy needed generally decreases as you move down a group
Electrons are farther from the nucleau
Shielding effect

9. Periodic Trends: Chapter 14.2
Periodic Trend (ionization energy cont. )
As you move from left to right across a period, ionization energy generally increases.
Increase in atomic # means a stronger attraction of the positive nucleus to the electrons.

10. Ionization Energy vs. Atomic Number

11. Periodic Trends: Chapter 14.2
3. Ionic Size:
The size of the ion as it gains (non-metals) or loses (metals) electrons.
Group Trend:
Positive Ions (cations/metals) and Negative Ions (anions/ nonmetals) increase in ionic size as you move down a group.
Periodic Trend:
Cations and Anions generally decrease as you move across a period.

12. Periodic Trends: Chapter 14.2
4. Electronegativity: the affinity of an atom for electrons- its tendency to attract electrons
Group Trends: As you move down a group electronegativity decreases (Fr = least electronegative)
Electrons are farther from the nucleus
Shielding effect.

13. Periodic Trends: Chapter 14.2
Electronegativity cont.
Periodic Trends: As you move across a period, electronegativity increases. ( F = most electronegative element)
Because of smaller atomic radius and ionic size

14. Electronegativity vs. Atomic Number

15. Periodic Trends: Chapter 14.2
5. Metallic Character:
The metallic character of an element can be defined as how readily an atom can lose an electron.
Group Trend: as you move down a group, metallic character increases
Fr- the most metallic element
Periodic Trend: as you move from left to right across a period, metallic character decreases.