What elements form ionic compounds? How is an ionic bond formed?

What’s a chemical bond? A chemical bond is the force that holds two atoms together Two types of chemical bonds: Ionic Covalent

Why do atoms form bonds? Formation of chemical bonds is due to number of valence electrons Why do valence electrons play such an important role? Because elements react to get the stable electron structure of a noble gas How many electrons do atoms want to have in their outermost energy level? 8

The Octet Rule States that atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons Why? This is the stable electron configuration of the noble gases How do we know if they will gain or lose electrons? Atoms will do what is easiest to get the most stable electron configuration. Atoms with 1, 2 or 3 valence electrons will ___________ electrons. lose Atoms with 5, 6 or 7 valence electrons will ___________ electrons. gain

How do atoms form bonds? One way is by the formation of ions. An ion is an atom (or a group of bonded atoms) with a positive or negative charge. - Proton - Neutron - Electron What would be the easiest way this sodium atom could get the perfect 8? Sodium Atom Sodium Ion

Positive or Negative Ion? How can you tell if the ion formed will be positive or negative? Count the protons and electrons How many protons? ___ How many electrons? ___ What’s the charge? ___ 11 How many protons? ___ How many electrons? ___ What’s the charge? ___ 11 11 10 +1

Ions What type of atoms form positive cations? Metals What type of atoms form negative anions? Nonmetals Exceptions: Lets take a look…

Group Charges All alkali metals have a charge of _____. +1 All alkali metals have a charge of _____. All alkaline earth metals have a charge of _____. All halogens have a charge of ____. Group 6A elements have a charge of ____. +2 -1 -2

Practice Questions Which type of atoms form cations? Which type of atoms form anions? Is Na+ a cation or anion? Is F- a cation of anion? Is Ca2+ a cation or anion? Is Mg2+ a cation or anion? What is the charge of the iodine ion? What is the name of the iodine anion? Would oxygen form a cation or anion? What is the net charge of zinc (II)? metals nonmetals cation anion cation cation -1 iodide anion 2+

Naming Ionic Compounds The “Swap & Drop” Method

Electron Dot Structure or Lewis Dot Diagram A notation showing the valence electrons surrounding the atomic symbol.

Binary Compounds Monatomic ions bond together to form Binary compounds. Ex: Na+ + Cl-  NaCl Cation (1st) Anion (2nd) in an ionic compound Cation + Anion  Ionic Compound

Na Cl - + 1 1 Swap & Drop Method For Ionic Compounds Only! Sodium Ion Na Chlorine Ion Cl - + 1 1 Step 1: Write the element symbol and the charge on the ion

Na Cl 1 1 Swap & Drop Method Step 2: Swap Values. Sodium Ion Chlorine Ion Cl 1 1 Step 2: Swap Values.

K Cl 1 1 1 1 Swap & Drop Method Step 3: Drop Values to Subscripts. Potassium Ion K Chlorine Ion Cl 1 1 1 1 Step 3: Drop Values to Subscripts.

Swap & Drop Method Potassium Ion K Chlorine Ion Cl Potassium Chloride Step 4: When the values are the same, then they can be erased. The number (1) is never required.

Al O - + 3 2 Swap & Drop Method Aluminum Ion Al Oxygen Ion O - + 3 2 Step 1: Write the element symbol and the charge on the ion .

Al O 3 2 Swap & Drop Method Step 2: Swap Values. Aluminum Ion Oxygen Ion O 3 2 Step 2: Swap Values.

Al O 2 3 2 3 Swap & Drop Method Step 3: Drop values to subscripts. Aluminum Ion Al Oxygen Ion O 2 3 2 3 Step 3: Drop values to subscripts.

Al O 2 3 Swap & Drop Method Step 4: Combine into compound. Aluminum Ion Al Oxygen Ion O 2 3 Aluminum Oxide Step 4: Combine into compound.

Names of Ions A positively charged ion is called a cation. A cation’s name is the same as the element A negatively charge ion is called an anion. An anion’s name has the ending “–ide” added to the root name Example: Anion of chlorine is the chloride ion. 1. What is the oxygen ion called? oxide 2. What is the fluorine ion called? fluoride 3. What is the bromine ion called? bromide

Common Polyatomic Ions Formed when more than one atom are grouped together Charge on polyatomic ions applies to entire group of atoms. The polyatomic ion acts as an individual ion and is protected with parenthesize in the formula! Typically end in –ate or -ite Common Polyatomic Ions NH4+ Ammonium NO3- Nitrate OH- Hydroxide CO32- Carbonate SO42- Sulfate PO43- Phosphate NO2- Nitrite Sulfate Carbonate

Transition Metal Rules Roman Numerals Polyatomic Ions

Transition Elements How many valence electrons do transition elements have? Two (electron config: ns2) They will commonly lose those two valence electrons to form ions with a +2 charge But….they can also lose some of their d electrons to form ions of +3, +4 or greater Some are consistent: Fixed Charge Called the reverse stair case Ex: Zn+2, Cd+2, Ag+1 Some elements act like transition metals Ex. Sn and Pb

Roman Numerals System used to indicate numbers II = 2 III = 3 IV = 4 V = 5 We use Roman Numerals when naming to indicate charge of transition metals Copper (II) = Copper +2 Iron (II) = Iron +2 Chromium (III) = chromium +3 Transition Metals with Fixed charges DO NOT get roman numerals: Silver +1, Zinc +2, Cadmium +2