1. Making Bonding Models

2. Today We Will…
Describe the two main ways elements bond
Construct Lewis Dot Diagrams
Identify characteristics of Ionic and Compounds
Define cation and anion

3. Bonding
Bonding is the sharing or transferring of electrons between elements in order to combine to form molecules or compounds.
Bonding is the sharing or transferring of electrons between elements in order to combine to form molecules or compounds.

4. Types of Bonds
Metal + Nonmetal = Ionic (transfer) Nonmetal + Nonmetal = Covalent (share) Metal + Metal = Metallic (sea of electrons)

5. Bonding possibilities
(1) They can try to gain electrons to fill up their last shell. (IONIC) OR
(2) They give up electrons and have a filled lower shell. (IONIC)
(3) They share a few electrons and have a filled shell. (COVALENT)
gain
Give
share

6. Lewis Dot Diagrams Discovered by Lewis
It is a diagram for each element that depicts that element’s valence electrons
Valence Electrons: electrons on the outer shell of an element.
This will help
us tell how
elements will
bond!!!

7. Learning Check A. X would be the electron dot formula for
A. X would be the electron dot formula for
1) Na 2) K 3) Al
 
B  X  would be the electron dot formula
1) B 2) N 3) P

8. How do we know the valence electrons of an element?
GROUPS!!
Label the valence electrons according to their groups.

9. Ionic Bond
Definition:-bond formed between two ions by the transferring of electrons
Ionic bonds only form between a metal and a nonmetal with different electronegativities.
Electronegativity- tendency of an atom to attract electrons
The more electrons the atom has the more elctronegative it is.
Definition: bond formed between two ions by the transfering of electrons
Metals become cations (positively charged ions)
Nonmetals become anions (negatively charged ions)

10. Which has the highest electronegativity

11. Ionic Bonds form Ions Metals become cations (+ charged)
Nonmetals become anions (-charged)

12. Octet Rule = atoms tend to gain, lose or share electrons so as to have 8 electrons
C would like to
N would like to
O would like to
Gain 4 electrons
Gain 3 electrons
Gain 2 electrons

13. Helium, neon and argon are atoms which do not react with other atoms.
Each of these gases has a full outer electron shell (orbit).
10p10n
18p22n
2p2n 4 Ne 20 He 2 10 Ar 40 18
2,8
2,8,8

14. The Sodium atom has 1 Electron in it’s outer shell.
Chemical Bonds.mht Na
The Sodium atom has 1 Electron in it’s outer shell.
e.c. 2,8,1
Atom +
The Sodium loses 1 electron to leave a complete outer shell.
It is now a Sodium ion with a charge of 1 +
(Na +)
e.c. (2,8)+
Ion
All Things Science - Ionic and covalent bonding animation.mht

15. The Chlorine atom has 7 electrons in it’s outer shell.Cl
e.c. 2,8,7
Atom -
(Cl - )
The Chlorine gains 1 electron to gain a complete outer shell.
It is now a Chlorine ion with a charge of 1 -
e.c. (2,8,8)-
Ion

16. Oxidation Numbers
The plus or minus indicates if electrons were lost or gained.
The number indicates how many electrons.
Oxidation numbers tell the number of electrons an atom gained or lost when forming the compound.
The plus or minus indicates if electrons were lost or gained.
The number indicates how many electrons.

17. Ionic Bond
Write the symbol for each element
Draw the Electron Dot Diagram
Draw an arrow to show the transfer of electrons
Make sure the sum of the ions equals zero

18. Ionic Bond
Write the symbol for each element
Draw the Electron Dot Diagram
Draw an arrow to show the transfer of electrons
Make sure the sum of the ions equals zero

19. Magnesium (Mg) + Fluorine (F)
Ionic Bond
Magnesium (Mg) + Fluorine (F)
Don’t forget to show the oxidation number and the chemical formula.

20. Ionic Compounds High melting points and boiling points
Held together by strong electrostatic forces
High melting points and boiling points
When melted or dissolved ionic compounds conduct electricity

21. Covalent Bonding

22. Today We Will Describe and draw covalent bonding
Identify characteristics of covalent compounds
Define diatomic atom

23. Lets Review
How many valence electrons makes an atom stable? What is this called?
Draw the Lewis Dot Diagram for Sulfur
An ionic bond is between a _______ and a ______.
An ionic bond forms when electrons are _______ or _______.

24. Atoms still want to achieve a noble gas configuration.
Covalent Bond
Atoms still want to achieve a noble gas configuration.
Bond formed by sharing electrons
Occurs between non metals
Results in the formation of a molecule
1. sharing

25. Covalent Bond
Write the symbol for each element
Draw the Electron Dot Diagram
Rearrange the electrons to pair up with electrons from each atom
Draw circles to show sharing of electrons
Draw the bond structure for each pair of electrons shared.

26. Hydrogen (H) + Hydrogen (H)
Covalent Bond
Hydrogen (H) + Hydrogen (H) H° °H
Each hydrogen atom wants to gain one electron to achieve an octet
The octet is achieved by each atom sharing the electrons in the middle.

27. Hydrogen (H) + Hydrogen (H)
Covalent Bond
Hydrogen (H) + Hydrogen (H) H° °H
The pair shared in the middle is called a bonding pair. Since there is only one bonding pair we call this a single bond.

28. Hydrogen (H) + Hydrogen (H)
Covalent Bond
Hydrogen (H) + Hydrogen (H) H H
Single bonds are represented with a dash.

29. O Oxygen atoms are highly electronegative.
So both atoms want to gain two electrons.

30. Both electron pairs are shared.

31. O O
6 valence electrons
plus 2 shared electrons
= full octet

32. O O
two bonding pairs,
making a double bond

33. Diatomic Atoms
Elements that are naturally in molecules with 2 atoms each
H O N Cl Br I F

34. Covalent Compounds Forces between molecules are weak.
Usually gas or liquids
Low melting point and boiling point
No overall electrical charge

35. Classwork/Homework
H2S F2 HF
H2O
AlF3
MgO
NH3
PBr3
CCl4
CS2
CO2
K2S
CH4