1. Trends of the Periodic Table
Exceptions, shortcuts and periodic trends (6.3)

2. Learning Targets You will:
Know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
Determine how to write electron configuration and orbital notation for atoms and ions.
Compare and contrast atoms and ions based on periodic trends.

3. Exceptions Chromium (Cr) and copper (Cu)
Completely full or half full d sublevel is more stable than a partially filled d sublevel
Cr (expected): 1s2 2s2 2p6 3s2 3p6 4s2 3d4
Cr: 1s2 2s2 2p6 3s2 3p6 4s1 3d5
Cu (expected): 1s2 2s2 2p6 3s2 3p6 4s2 3d9
Cu: 1s2 2s2 2p6 3s2 3p6 4s1 3d10
You will determine how to write electron configuration and orbital notation for atoms and ions.

4. Noble Gas Configuration
An example of this (Gallium):
full: 1s22s22p63s23p64s23d104p1
noble gas short cut: [Ar] 4s23d104p1
The noble gas that precedes the element is the noble gas used in the shortcut.
Its electron configuration is replaced with the noble gas in brackets.
Remaining electron configuration is written after.
Noble gases = group of elements w/filled electron cloud
Found in group 8 or 18
Stable and relatively inert or unreactive
Easier way to write a full configuration

5. Examples Answers: Br: [Ar]4s23d104p5 Sn: [Kr]5s24d105p2
Write the electron configuration using the noble gas shortcut for:
bromine (Br)
tin (Sn)
pollonium (Po)
fluorine (F)
Answers:
Br: [Ar]4s23d104p5
Sn: [Kr]5s24d105p2
Po: [Xe]6s24f145d106p4
F: [He]2s22p5

6. Examples

7. Try on your own Answers: Si: [Ne]3s23p2 Pb: [Xe]6s24f145d106p2
Write the electron configuration using the noble gas shortcut for:
silicon (Si)
lead (Pb)
iodine (I)
cesium (Cs)
Answers:
Si: [Ne]3s23p2
Pb: [Xe]6s24f145d106p2
I: [Kr]5s24d105p5
Cs: [Xe]6s1

8. Try on your own

9. Isoelectronic Ions
Atoms or ions that have the same electronic structure
anhd/C101webnotes/ch emical- bond/isoelectronic.html
You will determine how to write electron configuration and orbital notation for atoms and ions.

10. Practice Write the electron configuration for the magnesium ion.
Write the electron configuration for the phosphorus ion.
1s2 2s2 2p6
1s2 2s2 2p6 3s2 3p6
You will determine how to write electron configuration and orbital notation for atoms and ions.

11. Try on your own
Write the electron configuration for neon. Name one positive ion and one negative ion with the same configuration.
1s2 2s2 2p6
Na+, Mg2+, Al3+, N3-, O2-, F-
You will determine how to write electron configuration and orbital notation for atoms and ions.

12. You will compare and contrast atoms and ions based on periodic trends.
Valence Electrons
Electrons in the outermost (highest) principal energy level of an atom
Important for atom bonding
Number corresponds to group number (except He)
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

13. You will compare and contrast atoms and ions based on periodic trends.
Examples
The halogens contain how many valence electrons?
Sodium has how many electrons in its outermost principal energy level?
The alkali earth metals have how many valence electrons?
The noble gases contain how many valence electrons? 7 1 2 8
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

14. Atomic Size (also radii and radius)
Measure of atom size
Extremely small, often measured in picometers (pm)
Typical distance from center of nucleus to boundary of electron cloud
Increases moving to left on period
Increases moving down a group
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

15. Atomic Size (also radii and radius)
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

16. You will compare and contrast atoms and ions based on periodic trends.
Examples
Which of the following atoms has the largest atomic radius? (Na, Mg, Si, P)
Which of the following atoms has the smallest atomic radius? (As, Sb, Bi, P)
Which of the following has the largest atomic radius? (Na, Mg, P, N)
Which of the following has the smallest atomic radius? (N, F, Br, Cl) Na P F
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

17. You will compare and contrast atoms and ions based on periodic trends.
Ionic Radii
Closely linked to atomic radii
Neutral atom gains or loses electrons creating anions or cations
Depending on that loss or gain, atom’s radius increases or decreases
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

18. You will compare and contrast atoms and ions based on periodic trends.
Ionic Radii
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

19. You will compare and contrast atoms and ions based on periodic trends.
Ionization Energy
Energy required to remove an electron, loosely bound valence electron, from an individual atom in the gas phase
Energy required to remove first electron is called first ionization energy
Increases moving across a period
Increases moving up a group
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

20. You will compare and contrast atoms and ions based on periodic trends.
Ionization Energy
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

21. You will compare and contrast atoms and ions based on periodic trends.
Interpret Data
What are the values for the first, second and third ionization energies for sodium and aluminum?
Is it easier to remove an electron from a sodium (Na) or aluminum (Al) atom? From Na+ or Al+? From Na2+ or Al3+?
Which ion is more common – Na3+ or Al 3+?
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

22. You will compare and contrast atoms and ions based on periodic trends.
Examples
Which of the following has the highest ionization energy? (Ca, C, N, O)
Which of the following atoms has the highest ionization energy? (Mg, Si, P, Cl)
Which of the following atoms has the highest ionization energy? (Al, Si, P, As) O Cl P
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

23. You will compare and contrast atoms and ions based on periodic trends.
Electronegativity
Measure of an atom’s tendency to attract shared electrons
Pauling scale used
Fluorine is the most electronegative atom
Increases moving across period
Increases moving up a group
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

24. You will compare and contrast atoms and ions based on periodic trends.
Electronegativity
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

25. You will compare and contrast atoms and ions based on periodic trends.
Electron affinity
A neutral atom’s likelihood of gaining an electron
The less valence electrons, the least likely an atom will gain electrons
Increases across a period
Increases up a group
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

26. You will compare and contrast atoms and ions based on periodic trends.
All the trends …
You will know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
You will compare and contrast atoms and ions based on periodic trends.

27. Learning Targets You will:
Know the trends of the periodic table: atomic radii, ionic radii, electronegativity, ionization energy, electron affinity
Determine how to write electron configuration and orbital notation for atoms and ions.
Compare and contrast atoms and ions based on periodic trends.