1. Stability in Bonding Ch. 20 Section 1
Ch. 20 Chemical Bonds
Stability in Bonding
Ch. 20 Section 1

2. Bell Work
Good morning! Today is October 14. I hope you all had a great Fall Break! We are now on Chapter 20, Section 1 (page 602 in your book). Please get started on the Bell Work quietly.
1). Explain why some elements are stable on their own while others are more stable in compounds?
2). Describe why chemical bonding occurs. Give two examples of how bonds can form.
3). Compare and contrast the properties of the individuals elements that combine to make salt with the compound salt. (NaCl)

3. Answers
1). If an element has eight electrons in its outer electron energy level, it has a tendency not to react.
2). Electrons are either gained, lost, or shared between atoms.
3). Sodium, as an elements, is a solid metal. Chlorine is a gas. When the two combine to form sodium chloride, they form a solid compound.

4. Warm Up
Sodium is in group one of the periodic table. A sodium atom has one valence electron. Atoms with one electron in their outer energy levels will bond easily with atoms having 7 valence electrons. Name one element sodium could give its one extra electron to.

5. Combining Elements
Many elements exist around you in their uncombined forms, but elements can unite chemically to form compounds when conditions are right

6. Combining Elements
Compounds often have properties unlike the properties of their individual elements

7. Combining Elements
A Chemical Formula tells what elements a compound contains and the exact number of atoms of each element in a unit of the compound

8. Combining Elements
A subscript is written after and below the element’s symbol
Subscripts tell how many atoms are in each unit of a compound
NH3

9. Atomic Stability
An atom is chemically stable when its outer energy level is complete (like the Noble Gases)
Other elements are more stable when they can complete their outer energy levels by becoming part of a compound

10. Atomic Stability
The Octet Rule says that atoms tend to combine so they have 8 electrons in their outer energy level
Atoms can gain, lose, or share electrons to complete their outer energy levels and become stable
Gaining, losing, and sharing electrons forms an attraction between atoms

11. Atomic Stability
The attraction is called a Chemical Bond, and atoms are pulled together, forming a compound

12. Atomic Stability
Generally, ionic bonds are formed between a metal and a nonmetal, and covalent bonds are formed between two or more nonmetals
Electronegativity is the ability of atoms to attract electrons within a bond – this determines the bond type