1. Bond
Day 2: #4

2. Chemical Bond
TEK I7D – relate the chemical behavior of an element including bonding, to its placement on the periodic table
Day 2: #4

3. Before there were bonds, there had to be elements
Before there were bonds, there had to be elements! Let’s review elements & the Periodic Table
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Review the periodic table with the students. (Groups, periods, valence electrons)

4. Periodic Table: Group Period Periods – horizontal rows
Groups or Families – vertical columns
Elements in the same group have similar chemical properties!
Group
Period

5. Atomic number = # protons and it identifies the element!!!!!HI D E

6. Valence Electrons – electrons involved in bonding; all atoms “want” to have 8 or 0 valence electrons to make them “happy and stable .” The numbers in purple are the # of valence electrons the atoms in those groups have. HI D E 3 4 5 6 7 2

7. Metals (pink elements) usually have 1, 2, or 3 valence electrons
Metals (pink elements) usually have 1, 2, or 3 valence electrons. In order to have 0 or 8 valence electrons, do you think a metal will lose or gain valence electrons? HI D E 3 4 5 6 7 2

8. Metals will lose electrons and become positive ions
Metals will lose electrons and become positive ions! Group 1 metals lose 1 ve- (which = 0 ve-) Group 2 metals lose 2 ve- (which = 0 ve-) Group 3 metals lose 3 ve- (which = 0 ve-) Remember to think about the easiest way to reach 0 or 8! HI D E 3 4 5 6 7 2

9. When an atom loses or gains ve- it becomes an ion
When an atom loses or gains ve- it becomes an ion! Losing 1 ve- makes an ion with a +1 charge. Losing 2 ve- makes an ion with a +2 charge. Losing 3 ve- makes an ion with a +3 charge. HI D E 3 4 5 6 7 2

10. Nonmetals (yellow elements) usually have 5, 6, 7, or 8 valence electrons. In order to have 0 or 8 valence electrons, do you think a nonmetal will lose or gain valence electrons? HI D E 3 4 5 6 7 2

11. Nonmetals will gain electrons and become negative ions
Nonmetals will gain electrons and become negative ions! Group 15 (5 ve-) nonmetals gain 3 ve- (which = 8 ve-) Group 16 (6 ve-) nonmetals gain 2 ve- (which = 8 ve-) Group 17 (7 ve-) nonmetals gain 1 ve- (which = 8 ve-) Remember to think about the easiest way to reach 0 or 8! HI D E 3 4 5 6 7 2

12. When an atom loses or gains ve- it becomes an ion
When an atom loses or gains ve- it becomes an ion! Gaining 3 ve- makes an ion with a -3 charge. Gaining 2 ve- makes an ion with a -2 charge. Gaining 1 ve- makes an ion with a -1 charge. HI D E 3 4 5 6 7 2

13. What about Group 18 (the Noble Gases)
What about Group 18 (the Noble Gases)? They already have 8 valence electrons so they are already “happy” and stable. They are the “perfect” elements and are considered unreactive! HI D E 3 4 5 6 7 2

14. What are Chemical Bonds?
An attraction between two or more atoms
Interaction between
valence electrons
All atoms need 0 or 8
valence electrons to
be “happy” or stable

15. Two Kinds of Bonds Ionic Bonds
-form ionic compounds between metals and nonmetals
-by losing /gaining electrons
Covalent Bonds
-form covalent compounds
-by sharing electrons

16. 1. An unidentified element has many of the same
physical and chemical properties as
magnesium and strontium but has a lower
atomic mass than either of these elements.
What is the most likely identity of this
element?
F Sodium
G Beryllium
H Calcium
J Rubidium
Answer:G
Question from TEA released TAKS test
Day 2: #4

17. 2. The elements of which of these groups on the periodic table are most resistant to forming compounds?
A Group 1
B Group 9
C Group 14
D Group 18
Answer:D
Question from TEA released TAKS test
Day 2: #4

18. 3. The elements from which of the following
groups are most likely to react with
potassium (K)?
F Group 2
G Group 7
H Group 13
J Group 17
Answer: J
Question from TEA released TAKS test
Day 2: #4

19. 4. Which of the following groups contains
members with similar chemical reactivity?
A Li, Be, C
B Be, Mg, Sr
C Sc, Y, Zr
D C, N, O
Answer: B
Question from TEA released TAKS test
Day 2: #4

20. 5. According to the periodic table, which element most readily accepts electrons?
A Fluorine
B Nitrogen
C Arsenic
D Aluminum  
Answer: A
Question from TEA released TAKS test
Day 2: #4

21. 6. Elements in Group 16 of the periodic table usually —
F form large molecules
G gain electrons when bonding
H act like metals
J solidify at room temperature
Answer: G
Question from TEA released TAKS test
Day 2: #4