1. Elements
# of Protons
# of neutrons
# of electrons
Mass #
Atomic
Lithium
#1. 3
#2. 4
#3. 3
#4. 7
#5. 3
Carbon
#6. 6
#7. 6
#8. 6 12 6
Chlorine 17 19 36
Silver 47 61
108
lead 82
125
207

2. Ch.12 Section 2 Grouping the Elements
Explain why elements in a group often have similar properties
Describe the properties of the elements in the groups of the periodic table

3. Periods
As you move from left to right across a row, the elements become less metallic

4. Group 1: Alkali Metals Are the most reactive metals
Have one outer energy level electron
Pure alkali metals are stored in oil to keep them from reacting with water and oxygen in the air.
Only found in nature combined with other elements
Like table salt (sodium chloride)

5. Group 2: Alkaline-Earth Metals
Very reactive but less reactive than group 1
Have 2 electrons in the outer energy level
Calcium is found in cement, chalk, and your bones and teeth.

6. Group 3-12: Transition Metals
Are less reactive than group 1 or 2
Examples being passed around are Zinc and Copper
Properties
Shiny
Malleable- can be hit with a hammer and not shatter
Can conduct electricity
Can conduct thermal energy

7. Lanthanides and Actinides
They are from periods 6 and 7
They are found at the bottom of the periodic table
Lanthanides are used to make steel
Actinides are radioactive because they are “unstable”

8. Group 13: Boron Has 3 electrons in the outer energy level Reactive
The most common element in group 13 is aluminum (the most abundant metal in the Earth’s crust)

9. Group 14: Carbon Group Has 4 electrons in the outer energy level
Carbon forms compounds such as proteins, fats, and carbohydrates which are important to your diet.
Diamonds and Coal have very different properties, yet both are natural forms of carbon
Silicon and germanium are used to make computer chips

10. Group 15: Nitrogen Group Have 5 electrons in their outer energy level
Nitrogen is a gas at room temperature and makes up 80% of the air you breathe.

11. Group 16: Oxygen Group Has six electrons in the outer energy level
Oxygen is also a gas at room temp and only makes up 20% of air. Oxygen is necessary for substances to burn.

12. Group 17: Halogens Has 7 electrons in the outer energy level
They are VERY reactive NONMetals because their atoms only need to gain one electron to have a complete outer level ( 7+1=8 and 8 is the most you can have!)
Chlorine and Iodine are examples of Halogens

13. Group 18: Noble Gases Have 8 electrons in the outer energy level
They are Unreactive nonmetals.
Helium is a noble gas that’s low density allows it to float

14. Hydrogen
The properties of H do not match the properties of any single group, so H is set apart from other elements on the periodic table.
H has only 1 electron, thus they have 1 electron in the outer energy level
H is the MOST ABUNDANT element in the universe
It is a colorless and odorless gas