Types of Bonding

There are two types of bonds: Ionic bonds Covalent bonds

IONIC BONDING

Ionic Bonding Occurs between a metal and a nonmetal Ionic Bond - Electrons are transferred from one atom to the other

Properties Ionic compounds have high melting points (meaning they are very strong) Ionic compounds are also very brittle Ionic compounds usually dissolve in water (these solutions are good conductors of electricity)

The Octet Rule Octet Rule – atoms tend to gain, lose, or share electrons in order to acquire a full set (8) valence electrons Remember that is the goal of atoms to have the electron configuration of noble gases

Lewis Dot Diagrams The valence electrons are the only ones that will participate in bonding so we will concentrate on those. In Lewis Dot Diagrams we use dots to represent electrons around the symbol of an element to allow people to see how many valence electrons they have

An Example: Carbon has 4 valence electrons: We use the dots to represent the valence electrons! C

Draw the Lewis dot structures for Li + O What is the formula? Li 2 O Li O

Writing Ionic Bonds

Recap Ionic bond forms between- –metal and a non-metal Electrons are- –transferred from the metal to the non-metal

Rules for writing the formula 1.Write the symbol and the oxidation number (common ion), putting the positive charge first. 2.Switch the oxidation numbers, re-write them as subscripts without their charges. 3.Reduce the subscripts if you can.

EX Magnesium and Oxygen

Transition Metals What is their common ion?? –It will change depending on the element that they are bonding with. Roman numerals will tell you the oxidation number. It’s always given to you.

EX Nickel (IV) and Sulfur

Your turn Write the chemical formula for the following ionic compounds Sodium and iodine Barium and oxygen Potassium and sulfur Magnesium and phosphorous

Polyatomic Ions We have dealt with ions like Na+ or Cl- …those are monatomic ions (ions consisting of only one atom). Another important group exists…polyatomic ions. They consist of more than one atom and still have either a positive or negative charge.

Polyatomic ion- Names sometimes end in –ate or –ite **Rules stay the same for bonding but also… –Treat the ion like a single atom –Always use ( )

EX Calcium Perbromate Never Change what is inside the ( )- Cannot be reduced because the 4 is inside the ( )

Your turn Write the formula for the following compounds: – Sodium and chlorate – Barium and nitrate – Ammonium and selenium – Ammonium and phosphate

Two Types of Ionic Compounds Binary- consists of only 2 types of elements (ex: HBr) Ternary- consists of more than 2 types of elements (ex: NaNO 3 ) –These will have polyatomic ions

How to Name- binary 1.Write the name of the first element from the periodic table 2.Write the name of the second element drop the ending and add –ide Some examples: a) NaCl is sodium chloride b) BaF 2 is barium fluoride Now you try: c) Al 2 S 3 and d) CaO

How to Name- ternary 1.Write the name of the first element from the periodic table 2.Write the name of the second group just like it is on the list Some examples: a) KNO 3 is potassium nitrate b) MgSO 3 is magnesium sulfite Now you try: c) CaCO 3 and d) NaOH

Exception Ammonium, NH 4 +1 Examples: NH 4 Cl and NH 4 NO 3 ammonium chloride ammonium nitrate

Practice Naming Compounds Determine if the compound is binary or ternary, then name it: 1. Li 3 P 2. Ca 3 N 2 3. KCl 4. NaClO 3 5. (NH 4 ) 2 Se Binary, lithium phosphide Binary, calcium nitride Binary, potassium chloride Ternary, sodium chlorate Ternary, ammonium selenide