1. Periodic Trends and Electron Shell Filling Model
PResentation

3. 7.11 Aufbau Principle and the periodic Table
As protons are added one by one to the nucleus, electrons are similarly added to the hydrogen-like orbitals
Aufbau allows us to determine the electron arrangement of an atom
Orbital filling diagrams tell us which orbital an electron is in when in ground state

6. Hund’s Rule
Tells us that the lowest energy configuration for an atom is the one that has the maximum number of unpaired electrons allowed by the Pauli rules
Basically start at 1s orbital level and move on from that point
Each orbital gets 1 electron first in a specific shell (S, P, D, F), and once everybody has 1 electron, we go back and give them a second buddy to fill the orbital space
Represented with arrows. Upward pointing arrow indicates the first electron, downward facing arrow represents the second electron

10. Periodic Table Vocabulary
1. Valence Electrons – Outermost electrons that any atom has
Elements in the same group share the same valence electron number
Elements in the same period share the same valence energy level
2. Transition Metals – “D block” metals.
Can have multiple charges, and some produce colored solutions
3. Lanthanide/Actinide Series -- “F block elements” Pulled out sections of table

11. Vocab
4. Main-Group Elements – Groups 1, 2, Basically the common elements
5. Metalloids -- On staircase, 7 elements with both metal/non-metal properties

12. 7.12 Periodic trends in atomic properties

13. Ionization Energy
Amount of energy required to remove the outermost electron from an element
As an element loses a valence electron, each successive valence electron requires more energy to “take” so first ionization energy is lowest value for this measurement

15. Group Trend in Ionization energy
Decreases as we move down any group on the table
As elements gain energy levels and shells, the force of attraction between the nucleus and its outermost electrons is reduced
So Fr would have the lowest ionization energy in group 1
And as one electron is removed the second ionization energy value increases significantly

16. Period Trend in ionization energy
Across a period ionization energy increases
This is because the effective nuclear charge increases as we move left to right across any period
The increased number of protons in the nucleus increases the nuclear attraction for the electrons in the atom, because of this it is more difficult to remove the outermost electrons from elements across any period
This is why non-metals do so well in bonding situations……they have strong nuclei

18. Electronegativity trends
Similar to ionization energy trends, decreases down a group, increases across a period
Trend holds true because the defining properties of the nucleus do not change
Greater effective nuclear charge across a period
Less of an effective nuclear charge down a group

20. Atomic radius
Increases down any group because of the addition of a new energy level as one moves from top to bottom
Decreases across a period because of the increase in the effective nuclear charge of each atom moving left to right
Once again, this explains why metals always lose electrons, and non-metals gain or at least share