Agenda Targets Element Review Elements Quiz Modeling Matter Writing Chemical Formulas Study Guide Going Home! Distinguish among a chemical symbol, formula, and a chemical equation. Determine the formula and name of a simple ionic compound, when provided with the anion’s and cation’s names and charges.

How does the water dissolve the ionic compounds? https://www.youtube.com/watch?v=xdedxfhcpWo

Agenda Targets Element review (Quiz Friday) Distinguish among a chemical symbol, formula, and a chemical equation. Determine the formula and name of a simple ionic compound, when provided with the anion’s and cation’s names and charges.

What makes up the elements? Protons Positive Charge Neutrons Neutral Charge Electrons Negative Charge

Elements & Ions Chlorine atom 17 protons 17 electrons Chloride ion (-1) 17 protons 18 electrons Oxygen atom 8 protons 8 electrons Oxide ion (-2) 8 protons 10 electrons Potassium atom 19 protons 19 electrons Potassium ion (+1) 19 protons 18 electrons

What changed when making an ion? The number of electrons changed, giving it a charge What happened to the charge when it gained electrons? negative charge (ANION) What happened to the charge when it lost electrons? positive charge (CATION)

Oxidation Numbers are used to determine the ratio in which elements combine to form compounds.

Understanding Chemical Formulas Chemical formulas are composed of a positive half and a negative half. Ex. - Water is a compound you know to have a formula of H2O.

For your graphic organizer Write above Cation (On Left) Anion (On Right)

The element with the positive oxidation number is always written first. The element with the negative oxidation number is always written second.

H O The total of the oxidation numbers in a compound must equal zero. +1 -2 H O Hydrogen’s oxidation number is +1 and oxygen’s is -2. With one H and one O, the total is not 0, it is -1!!!

Subscripts, small numbers to the lower right of the chemical symbol, represent the number of that element present in the compound. The subscript of 1 is never written in a chemical formula. It is understood since the chemical symbol is there. Add subscripts after a chemical symbol, when needed, to make the oxidation numbers total zero. H2O

How to check if the formula is correct: Multiply subscript by oxidation number for the total oxidation number of each element in a formula. For Hydrogen: (oxidation number +1)(subscript 2) = +2 total For Oxygen: (oxidation number -2)(subscript 1) = -2 total The formula H2O is the correct formula!!!

There MUST be an easier way....and there is!! Ca Cl The easiest way to think of writing chemical formulas is to use the oxidation number (without the + or -) of one element as the subscript of the other element. +2 -1 Ca Cl

Cross over the oxidation numbers without the charges!!! +2 -1 Ca Cl

Ca Cl 2 REMINDER: DO NOT write a subscript of 1. Reduce the subscripts if needed.

Naming Ionic and Molecular Compounds General Rules Positive ions (Cations) always come first Always have the name of the element For Example AgCl Begins with silver

How many of each element are there? HNO3 Na2C2O4 AgCl

What would the chemical formula be? H+1 O-2 Fe+2 Cl-1 Ag+3 (NO3)-3

Negative ion (Anions) comes next Here’s the hard part of naming If it is an element by itself You put –ide on the end For example AgCl Chlorine turns into chloride MgO Oxygen turns into oxide

Negative ion (Anion) If it is an element with an oxygen attached You put an –ate on the end For example SO4 Sulfur tetroxide turns into sulfate NO3 Nitrogen trioxide turns into nitrate

If the positive ion has more than one charge associated with it… You need to put the charge you have in parentheses in roman numerals For example Iron Has 2 charges, either +2 or +3 If we have iron +3 Iron (III) If we have iron +2 Iron (II)

Subtracting an oxygen gives you’re a new name Sulfate  sulfite (SO4  SO3) Nitrate  nitrite (NO3  NO2) Phosphate  phosphite (PO4  PO3) Carbonate  carbonite (CO3  CO2)

Other considerations… NH4  Ammonium HCO3  bicarbonate OH  hydroxide

9/10 Agenda Targets Practice before the races. Compound Naming and formula race. Trashball Review Fishkill articles and identify FACTS not opinions from incident. Determine the formula and name of a simple ionic compound, when provided with the anion’s and cation’s names and charges.