1. Chapter 5- Section 1 Arranging the Elements

2. A Russian chemist
named Dmitri Mendeleev was the first person to determine a pattern for the elements.

3. Mendeleev

4. Mendeleev noted that there was a pattern within the properties of elements. He could then organize the elements depending on their atomic mass.

5. What is the atomic mass of
an element?

6. Atomic mass is the weighted average of the masses of all of the naturally occurring isotopes of an element. It is measured in atomic mass units.

7. To calculate the atomic mass:
Multiply the mass# of each isotope (P+N) by its % amount in decimal form.
Add the two numbers together = atomic mass.
EXAMPLE:
Chlorine
Cl-35 (76% of chlorine in nature)
Cl-37 (24% of chlorine in nature)
(35x0.76)=26.6
(37x0.24)= 8.9
=35.5amu

8. Properties of Elements

9. The properties of elements change in a periodic way, which means in a regular, repeating pattern. This is how the periodic table got its name.

10. Can you think of something in your life that has a periodic pattern?

11. Some physical properties of elements include: color, density,atomic mass and luster

12. Some chemical properties of elements include:conductivity, flammability, and reactivity.

13. Periodic Law

14. The periodic law states that the chemical
and physical properties of elements are periodic functions of their atomic number.

15. In other words….. The # of protons or electrons in an atom will help determine its characteristics.

16. Understanding the Periodic Table

18. The periodic table may look confusing, but if you understand its pattern it will make more sense.

19. There are 3 main categories that elements are divided into metals, nonmetals and metalloids

20. What are some characteristics of each category?

21. Elements are placed into a specific groups based on their properties.

22. Location and Description of Elements

23. A zig zag line can be drawn on the periodic table to help remind you of the location of each type of element.

25. Border of line = Metalloids
Right of line=Nonmetals
Left of line = Metals
Border of line = Metalloids

26. Metals usually solid at room temp Shiny malleable (flattened)
ductile (made into wire)
good conductor of heat

27. Lithium

28. Sodium

29. Non Metals usually gas at room temp. non shiny
not malleable or ductile
poor conductor
brittle (can shatter)

30. Nitrogen

32. Metalloids
share properties of both
metals and nonmetals

33. Silicon

34. Boron