Recap and Section Intro

SECTION 3.2 NAMES AND FORMULAS OF SIMPLE COMPOUNDS Text pages 80-85

Recap So Far: Compounds are substances made of more than one type of element. – Ex: water is made of hydrogen and oxygen

Recap Each compound has a chemical formula: – Water’s chemical formula is H 2 O – Sodium chloride’s chemical formula is NaCl This tells you how many atoms or ions from each element are present in that compound.

With millions of different possible substances, how in the world could we come up with names for all of them??? Say whaaat??

Fortunately we have a system that tells us very quickly what type of elements we are dealing with in a compound. OH YEAH!!!

Since Ionic and Molecular compounds are made of different types of elements, there are different ways to name them!

Some compounds are given common names (like water, sugar, etc) in addition to more chemical names. Why might this be? Why might this be? Ahhh! Dihydrogen monoxide wave!!! Run!

NAMING IONIC COMPOUNDS

Naming Ionic Compounds Remember: Ionic compounds are made of metal and non-metal ions – NaCl is made of Na + ions and a Cl - ions in a 1:1 ratio (equal amounts of each!) – The chemical formula for ionic compounds will always start with the metal!

Steps for Naming Ionic Compounds Step 1: Name the metal ion first. It is the same as the element name! Step 2: Name the non-metal ion by ending the element name with the suffix “ide” Step 3: Put them together to get the name of the compound. Examples: NaCl and Mg 3 N 2

For non-metal elements that end in “ine”, it is very easy to change their name! Examples: Bromine  Fluorine 

But what about those that do not? It can be a little trickier! You will need to remember these: Oxygen Nitrogen Sulfur Phosphorous Selenium Hydrogen

you may have noticed that the number of metal ions or non-metal ions found in the compound DOES NOT change the name in any way Examples LiCl Li 2 O MgCl 2

Common ionic Compounds You must be familiar with the following: NaClCaCO 3 NaOH

NAMING MOLECULAR COMPOUNDS

Naming Molecular Compounds Note: Molecular compounds can also be called Covalent Compounds. It means the same thing. Remember: Molecular (also called covalent) compounds are made of only non-metal atoms (not ions!)

Unlike ionic compounds, we need to include the number of atoms in the name of molecular compounds. We include the number of atoms by using “prefixes” which are added before the element names (if needed).

Prefixes on board

Steps for naming Molecular Compounds: Step 1: Write the prefix for the first element ONLY if it has more than one atom Step 2: Add the name of the 1 st element to the prefix. The main part of the name does not change!

Steps for naming Molecular Compounds: Step 3: Leave a space and then write the prefix for the 2 nd element. Step 4: Add the name of the second element to the prefix and use the suffix “ide” Examples: SO 2, N 3 F 6, CO

Common molecular Compounds You must be familiar with the following: H 2 O = ________(iii) CH 4 = __________ C 6 H 12 O 6 = _______(iv) CO 2 = ________