1. Formula and Name of Covalent Compounds

2. Covalent Compounds
Figure 2.44: Sulfur hexafluoride (SF6) is a gas that does not conduct thermal energy well. It is used to insulate double-glazed windows.
Binary Covalent Compound: is a compound made up of the atoms of two elements joined by covalent bonds. The covalent compound to the right is called sulfur hexafluoride (SF6). So how do we create such a name for a covalent compound?
binary covalent compound: a compound made up of the atoms of two elements joined by covalent bonds

3. Writing Names of Binary Covalent Compounds
When writing the name of a covalent compound we need to:
Give a prefix and a name to the first element and
A prefix and a name to the second element.
The following table shows what prefix we give to both elements depending on how many atoms of each element make up the compound. If there is one atom the prefix is mono-, if there are two atoms we use the prefix di- and so forth…

4. Writing Names of Binary Covalent Compounds
A small note about the prefix mono:
Mono- is ONLY used for the second element in the covalent compound name.
If the first word in the name has only one atom, we don’t use the prefix mono-.
Since we don’t’ use mono- in this situation the non-use of it implies there is only one atom for the element.
Example: CO molecule has one carbon atom and one oxygen atom. The name of this molecule is Carbon Monoxide, it is not Monocarbon Monoxide.
Also, when mono- comes before -oxide, an “o” is dropped and we have monoxide, not monooxide.
binary covalent compound: a compound made up of the atoms of two elements joined by covalent bonds

5. Naming a Binary Covalent Compound
Problem:
What is the name of NO2?
Step 1: Name the leftmost element in the formula first.
The first element is N (nitrogen)
Step 2: Name the second element, making sure the name ends with the suffix –ide.
The second element is O (oxygen), which becomes oxide.

6. Naming a Binary Covalent Compound
Problem:
What is the name of NO2?
Step 3: Add a prefix to each element’s name to indicate the number of atoms of each element in a molecule of a compound. Remember, if the first element would get the prefix mono-, do not include that prefix.
The first element is nitrogen. There is 1 nitrogen atom. We do not use the prefix mono-
The second element is oxygen, which becomes oxide. There are 2 oxygen atoms. Add the prefix di- to oxide.
Therefore, the name of NO2 is nitrogen dioxide.

7. Naming a Binary Covalent Compound
Problem:
What is the name of H2O?
Step 1: Name the leftmost element in the formula first.
The first element is H (Hydrogen)
Step 2: Name the second element, making sure the name ends with the suffix –ide.
The second element is O (oxygen), which becomes oxide.

8. Naming a Binary Covalent Compound
Problem:
What is the name of H2O?
Step 3: Add a prefix to each element’s name to indicate the number of atoms of each element in a molecule of a compound. Remember, if the first element would get the prefix mono-, do not include that prefix.
The first element is hydrogen. There are 2 hydrogen atoms. Add the prefix di – to hydrogen.
The second element is oxygen, which becomes oxide. There is 1 oxygen atom. Add the prefix mono- (since this is the second element in the compound) to oxide.
Therefore, the name of H2O is dihydrogen monoxide.

9. Oxygen Tech vs Hydrogen U
When oxygen Tech played Hydrogen U. The Game had just begun, when Hydrogen scored two fast points And Oxygen still had none Then Oxygen scored a single goal And thus it did remain, At Hydrogen 2 and Oxygen 1 Called because of rain.

10. Practice Name the following Covalent Compounds: CH4 NF3 SeF6 B2Si
Si2Br6
P4S5

11. Practice – Answers Name the following Covalent Compounds:
CH4  Carbon Tetrahydride, AKA Methane
NF3 Nitrogen Trifluoride
SeF6  Selenium Hexafluoride
B2Si  Diboron Silicide
Si2Br6  Disilicon Hexabromide
P4S5  Tetraphosphorus Pentasulfide

12. Writing Formulas of Binary Covalent Compounds
Chemical formulas of binary covalent compounds indicate how many atoms of each element are present in a single molecule of a compound Example: SF6 (sulfur hexafluoride) 1 sulfur atom 6 fluoride atoms
binary covalent compound: a compound made up of the atoms of two elements joined by covalent bonds

13. Writing Formulas for Covalent Compounds
Problem:
What is the chemical formula for dinitrogen tetroxide?
Step 1: Write the element symbols in the order that they appear in the name.
Look at the periodic table to find the element symbols.
The first element is nitrogen, N.
The second element is oxygen (oxide), O.

14. Writing Formulas for Covalent Compounds
Problem:
What is the chemical formula for dinitrogen tetroxide?
Step 2: Add subscripts based on the prefixes used in the name.
The prefix di from dinitrogen tells you that there are 2 nitrogen atoms
The prefix tetr- from tetroxide tells you that there are 4 oxygen atoms.
Therefore, the formula of dinitrogen tetroxide is N2O4.

15. Practice Write the formula for the following covalent bonds:
Carbon Tetrachloride
Boron Trifluoride
Sulfur Dioxide
Hydrogen

16. Practice - Key Write the formula for the following covalent bonds:
Carbon Tetrachloride– CCl4
Boron Trifluoride - BF3
Sulfur Dioxide – SO2
Hydrogen – H2 (remember there are seven diatomic elements, Hydrogen is one of them.

17. Homework
Worksheet