1. Chapter 1: Materials
Section 2

2. Periodic Table
By the mid 1800s, scientists had discovered different elements!
Most of these elements had widely different
Scientists like began organizing these elements on Periodic Tables.

3. Periodic Table
kinds of Periodic Tables were generally produced and studied:
Periodic Tables organized by
Periodic Tables organized by “ “ .
Combining Capacity was the ratio elements would combine with each other.
Ex: elements like Cesium and Sodium combine 1:1 with atoms like

4. Periodic Table
Eventually, Tables started to be organized with elements of similar chemical properties in vertical .
Elements were also organized in Horizontal rows by atomic mass.
This served as the guidelines for the modern Periodic Table we use today!
Speaking of which, how many of the 1st 30 elements do you know? They’re fair game for quizzes coming up!

5. Electrical Nature of Matter
In order to understand how atoms and molecules work, we first have to understand the nature of matter.
We see this everyday in !
Balloons in hair, socks sticking to clothes, static shock, etc.

6. Electric Nature of Matter
THINK PAIR SHARE: Why does one end of a magnet attract another, but the other end repels that magnet?
Why: !
Atoms work the same way, there are and charges that attract!

7. Electric Nature of Matter
Atoms are made of three particles:
- Positive
- Negative
- Neutral
attraction between protons of one atom and electrons of another make the force that cause chemical bonds
(uncharged) atoms have same # of protons and electrons.

8. Modern Periodic Table
Today’s Periodic Table is organized by increasing
Atomic number is the number of protons, and since elements on the Table are neutral, also reflects electrons.

9. Modern Periodic Table
All of the mass of an atom is concentrated in the
The nucleus is a tiny, densely packed center of an atom, contains the and holding the mass of the atom, known as the .
Electrons take up the rest of space of the atom, but hold next to no mass.

10. Modern Periodic Table
All atoms of the same element ALWAYS have the same # of
# of Neutrons can differ, changing the mass #.
These different mass elements are called Isotopes
Examples:

11. Counting Subatomic Particles
Mass of a proton: 1 (amu)
Mass of a neutron: amu
Mass of an Electron: negligible (zero)
Derived from 1/12 of a atom
Mass #= # of Protons (simple math)
Remember: Atomic #= # of protons,
See chart on next page for practice

12. Periodic Table Practice
Element Symbol
Atomic #
Mass #
# of Protons
# of Neutrons
# of Electrons H 1 Na 12 B 11 5 17 18 40 21

13. Atomic Charges Protons=+1 Electrons=-1
If there’s more of one than another, the atom is
Examples:
Potassium with 19 Protons and 18 Electrons?-
Oxygen with 8 Protons and 10 Electrons?-
Helium with 2 Protons and 2 Electrons?-

14. Organizing the Periodic Table
Horizontal Rows of the table: Called
Trends across these Periods are called a
Vertical Columns of the table: Called or
Groups/Families have
Some have names, others only have labels (i.e. Group 3A)

15. Alkali Metals These metals are on group of the Table.
Highly , especially in water.
Examples:
Here’s a video showing what can happen with these metals in water:
Do we want to do our own???

16. Alkaline Earth Metals Group on the Periodic Table
Also reactive with water, more reactive with Chalcogen group like Oxygen (we will get to these)
Examples:
Heres a video on what happens when you burn magnesium:

17. Group 3A
No real ”Nickname” like Alkali Metals
Examples:

18. Group 4A Group 4A on the Table, still no Nicknames Examples:
Special property of Carbon: Makes 4 , really good for making big molecules
This is why much life is , but scientists think aliens out there could be

19. Group 5A
No Nickname, again… just 5A
Mildly .
Examples:

20. Chalcogens on the Periodic Table.
These elements are usually reactive than 5A.
Examples:
Interesting Question: Is Oxygen Killing us?

21. Halogens Group of the Table! Very ! These elements don’t mess around!
Examples:
Here’s what I mean: Pointing Fluorine at stuff:
2:40-5:15

22. Noble Gases Group of the Periodic Table
These gases are at all, hence the “Noble” gases.
Useful for keeping things from reacting!
Examples:

23. Periodic Properties
All of these properties shift as we go Periods of the Table
Hence, .
These allow us to predict what certain elements will act like!
Mendeleev: Predicted properties of Germanium before it was predicted.
THINK PAIR SHARE: If we discovered a new element in Group 2A, What might it be like?

24. Ions
These groups of our table, when reacted, can all form charged atoms
Recall: Charge practice earlier this section!
A atom is also referred to as an
Positive Ions:
Negative Ions:
Cations anions in what we call

25. Ions Ionic Bonds make special compounds: called
Happens when a readily gives up an electron to a
What happens when you lose a proton/gain an electron?
Result: charged atoms stick together. Often form crystalline structures

26. Metal Reactivity
Think Pair Share: Why do you think some metals corrode (rust) faster than others?
Answer:
As you move on the table: Metallic properties
As you move up/right: Metallic Properties
What this means: Cesium is metallic than Fluorine, and will corrode much faster than less metallic elements.(amongst other metallic properties).

27. Metals (continued)
With reactivity comes useful applications of metals: !
Some metals used in ionic compounds in fireworks:
Magnesium- Burns bright
Strontium- Burns
Copper:
Sodium/Calcium:
Barium-
Mix and match to get different colors!
Cool fireworks video: