1. K. Culbertson Chemistry 2013
Periodic Trends
K. Culbertson
Chemistry
2013

2. Disclaimer
You will take a quiz tomorrow on periodic trends. This will be your first grade for 2nd quarter.
Please review this presentation on the wiki this evening and come with questions tomorrow!

3. #1 Periodic Law
Elements are arranged by increasing … on the periodic table. In this arrangement, there are trends in properties.
A. Atomic Mass
B. Atomic Number
C. Number of neutrons B
Mosley – organized the elements on the periodic table in order of increasing atomic number

4. #2 Definitions
Which of the following describes the amount of energy needed to remove an electron from the outermost shell of an atom?
A. Atomic radius
B. Electronegativity
C. Ionization energy C

5. #3 Definitions
Which of the following describes the tendency for an atom to attract electrons?
A. Atomic radius
B. Electronegativity
C. Ionization energy B

6. #4 Definitions
Which of the following describes the distance from the nucleus to the outer electrons?
A. Atomic radius
B. Electronegativity
C. Ionization energy A

7. #5 Model Matching Which trend is represented by this model?
A. Atomic radius
B. Electronegativity
C. Ionization energy A

8. #6 Model Matching Which trend is represented by this model?
A. Atomic radius
B. Electronegativity
C. Ionization energy B

9. #7 Model Matching Which trend is represented by this model?
A. Atomic radius
B. Electronegativity
C. Ionization energy C

10. #8 Atomic Radius They get larger They get smaller
How do the configurations differ as you move down group 1A?
1s1
1s22s1
1s22s22p63s1
They get larger
They get smaller A

11. Atomic Radius Trends: Increases from top to bottom
Increased number of energy levels
Increases from right to left
Stronger nuclear charge on the right pulls electrons closer to the nucleus
In a period the electrons are all on the same principle energy level, they are pulled closer to the nucleus
The outer electrons are shielded from the nucleus by the complete inner shells

12. #9 Atomic Radius Questions to Ponder:
Would a cation (+ charge) be larger or smaller?
A. Larger atomic radius
B. Smaller atomic radius B
Cations are smaller than neutral counterparts because they lost an electron. The valence electrons feel a greater nuclear charge.
Anions are larger than neutral counterparts because they gained an electron. The nuclear charge decreases.
Would an anion (- charge) be larger or smaller?

13. Ionization Energy
The amount of energy required to remove the outermost electron of an atom of an element
Energy needed to remove an electron
Na + energy  Na+1 + e-

14. Ionization Energy Trends: Increases from left to right
Metals on the left side prefer to give up electrons to form a stable octet
Nonmetals on the right side want to take electrons, not give them up
Increases from bottom to top
Shielding makes it easier to remove electrons from larger atoms because the e- are farther away from the attraction of the nucleus

15. #10 Ionization Energy
What is the atomic number of the element with the highest ionization energy?
H-Ne only
2 - He

16. #11 Ionization Energy
If an atom has a lower ionization energy, then it is harder to remove an electron from its outermost shell.
A. True
B. False
F – it is easier

17. Electronegativty
The tendency for an atom to attract a pair of bonding electrons when it is combined with another atom in a chemical bond
Trends:
Increases from left to right
Nonmetals prefer to gain electrons, whereas metals prefer to lose electrons
Increases from bottom to top
The smaller the atom is, the greater the attraction felt by the nuclear charge

18. #12 Electronegativity
What is the atomic number of the element with the highest electronegativity?
H-Ne only
9 - F