1. Periodic Trends

2. Half of the distance between two bonding atoms nuclei
Atomic Radius
Half of the distance between two bonding atoms nuclei

3. Atomic Radius Trend
Increases
Increases

4. Atomic Radius Across a Period
Atomic radius generally decreases in size as you move left to right across the period
Increasing positive charge in the nucleus pulls the electrons of the same energy level in.

5. Atomic Radius Down a Group
Atomic radius increases as you move down a group
Orbital size increases as you move down a group with increasing energy level
Larger orbitals means that outer electrons are farther from the nucleus. This increased distance offsets the greater pull of the increased nuclear charge.
As additional orbitals between the nucleus and the outer electrons are occupied, the inner electrons shield the outer electrons from the pull of the nucleus this is called shielding.

6. Shielding
The inner electrons shield the outer electrons from feeling the pull of the nucleus

7. Ionic Radius Compare ions to their neutral counterparts
Ion: charged atom that results from the gaining or losing of electrons
Cation: loses electrons and produces a positive charge
Anion: gains electrons and produces a negative charge

8. Octet Rule
Atoms gain, lose, or share electrons to acquire a full set of eight valence electrons (to be like a noble gas)
Eight is great!!!

9. Cations and Anions Of Representative Elements+1 +2 +3 -3 -2 -1

10. Cation vs Atom

11. Cation Atom 12 electrons 10 electrons Mg2+ Mg Magnesium Cation
12 protons
12 electrons
12 protons
10 electrons
Mg2+
Magnesium Cation Mg
Magnesium Atom

12. Anion vs Atom

13. Anion Atom 18 electrons 16 electrons S Sulfur Atom S2- Sulfer Anion 16
protons
18 electrons
16 protons
16 electrons S
Sulfur Atom
S2-
Sulfer Anion

14. Cation is always smaller than atom from which it is formed.
Anion is always larger than atom from which it is formed.

15. Isoelectronic
have the same number of electrons, and hence the same ground-state electron configuration
N3-: 1s22s22p6 or [Ne]
O2-: 1s22s22p6 or [Ne]
F-: 1s22s22p6 or [Ne]
Na+: 1s22s22p6 or [Ne]
Al3+: 1s22s22p6 or [Ne]
Na+, Al3+, F-, O2-, and N3- are all isoelectronic with Ne

16. Periodic Table video

17. WUP#14 For the element Br find the following: Electron configuration
Excited state
Noble gas configuration
Orbital diagram

18. Periodic Trends day 2

19. Ionization Energy
Minimum energy required to remove an electron from a gaseous atom in its ground state
Indication of how strongly an atom’s nucleus holds onto its valence electron

20. What do you notice between successive ionization energies
What do you notice between successive ionization energies? What is the trend across and down?

21. General Trends in First Ionization Energies
Increasing First Ionization Energy
Increasing First Ionization Energy

22. Ionization Energy Trends – Across a Period
Ionization energy generally increases as you move left to right, including noble gases
Across a period electrons are added to the same energy level (same distance away from the nucleus), yet the nuclear charge is increasing across a period increasing the attraction to the electrons.

23. Ionization Energy Trends – Down a Group
Ionization energy decreases as you move down a group
Down a group electrons are added to a higher energy level (farther distance away from the nucleus), making it easier to remove an electron

24. Electronegativity
Indicates an element’s ability to attract electrons in a shared chemical bond
fluorine (F) is the most electronegative element
cesium (Cs) and francium (Fr)are the least electronegative
Noble gases do not tend to have an electronegativity number since they tend not to form compounds

26. F > O > Cl, N > Br > C, S > I > H , P
Electronegativity
Memorize!
F > O > Cl, N > Br > C, S > I > H , P
Frank Owes Claire Nine Brownies
Cause She Isa Hungry Person
*elements w commas between are = E.N.

27. Trends with Electronegativity
Electronegativity increases as you move left-to-right across a period
Electronegativity decreases as you move down a group