1. K. Culbertson Chemistry 2011
Periodic Trends
K. Culbertson
Chemistry
2011

2. Representative Elements
s & p blocks
Why representative elements? They exhibit a wide range of physical and chemical properties

3. #1 Periodic Law
Many of the physical and chemical properties of the elements tend to recur in a systematic manner with increasing atomic number
Periodic Trends
Trends that repeat at regular intervals (across periods or down groups)

4. #2a Atomic Radius The distance from the nucleus to the outer electrons
The size of an atom

5. #2b 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+ + e-

6. #2c Electronegativty
The tendency for an atom to attract a pair of electrons when it is combined with another atom in a chemical bond
Attraction for an electron of another atom

7. Why use straws?
To make a 3-D model of the properties of elements.

8. Atomic Radius of Oxygen
73 pm x 1 cm = cm
30 pm
2.4 cm (rounded to nearest tenth)

9. Ionization Energy of Neon
2081 kJ x 1 cm = 5.20 cm 400 kJ 5.2 cm (rounded to nearest tenth)

10. Electroneg. of Arsenic
2.2 (units) x 1 cm = 2.75 cm 0.8 (units) 2.8 cm (rounded to the nearest tenth)