Do Now1. Define electronegativity.2. What is a bond?3. What are the THREE types of bonds?4. What type of bond will form between…

Na and Cl??H and Cl??

Na and Na??

Ionic Bond• Transfer of electrons between metal and

nonmetal• Metals lose electron(s) to form positive ions

(cations)• Nonmetals gain electron(s) to form negative

ions (anions)

Covalent Bonds

• Sharing of electrons between two atoms (No ions!)• Typically all nonmetals

Why do some atoms

• Transfer electrons – resulting in an ionic bond…

While others

• Share electrons – resulting in a covalent bond?

Electronegativity

• Ability to attract electrons in a chemical bond• Go to page 170 in your book and

look up the electronegativity of Na, H and Cl.

Metallic Bonding• Metals are made up of closely packed cations

that are surrounded by mobile valence electrons

• Metallic bonds consist of the attraction of free-floating valence electrons for the cations

Determine what type of bond will form between…

• A) Li and Br• B) H and O• C) Ag and Ag• D) Ca and S• E) H and H• F) S and O

What are Valence Electrons?

• Electrons in the outermost energy level. • Usually the only electrons involved in

bonding• The group number will tell us the

number of valence electrons.• How many valence electrons does H, Mg,

S , Cl, Na have?

Electron Dot Structure• Diagram that shows valence electrons

as dots

X s__ p __ __ __

Draw Electron Dot Structures for … H, Mg, S, Cl, Na

To satisfy the Octet rule

• What will Na and Cl do?

• What will Mg and Cl do?

To satisfy the Octet rule

• What will H and Cl do?

• What will H and S do?

Do Now

• When atoms join together they form compounds. Differentiate between ionic and molecular compounds.

Properties of Ionic Compounds•At room temperature, most are crystalline solids •Have high melting points•When melted or dissolved, conduct electricity

Properties of Molecular Compounds•Some are solids, liquids, and gases.•Generally have lower melting and boiling points than ionic compounds.