Unit 7 (Naming and Formula Writing)

Question 1

Review of Ionic Compounds (Crystals)
1. transfer of what?
2. made from what 2 things?
3. what loses and what gains electrons?
4. chemical formula name and explanation
5. formula unit definition
6. are they electrically neutral??

Answer 1

• Transfer of electrons
• Made from a metal and a non-metal
• Metals lose electrons, nonmetals gain electrons
• Chemical formula is arranged in the smallest whole number ratio (empirical formula)
• Formula unit: the smallest repeating pattern within a crystal
• Even though ionic compounds are made up of ions, they ARE ELECTRICALLY NEUTRAL!

Question 2

Ions can be monatomic or polyatomic:

Answer 2

Monatomic: Made up of a single atom

Polyatomic: Made up of multiple atoms

Question 3

Polyatomic ions are made up of…

Answer 3

two or more elements covalently bonded together with an overall positive or negative charge.

(See polyatomic ion sheet to help)

Question 4

Review Molecular Compounds (Molecules)
* sharing of
* made from what?
* molecules of same compound are what and what of each other (the 2 I’s)
* chemical formula indicates what? What is it called?

Answer 4

• Sharing of electrons
• Made from nonmetals only
• Molecules of the same compound are IDENTICAL and INDEPENDENT of each other
• Chemical formula indicates the exact makeup of one molecule (molecular formula)

Question 5

What are the Rules for Formula Writing (Ionic Compounds)?
1. general rule about compounds and writing
2. roman numerals??
3. parenthesis rules, when optional, when required

Examples!

Answer 5

Since all compounds are neutral, figure out how many of each ion is needed to make a neutral compound. (Neutral means having a net zero charge.) Use periodic table to determine charge.
* Silver sulfate —-> Ag+1 Ag+1 (SO4)-2 —> Ag2SO4

Roman Numerals will always tell you the charge and it will always be positive.
* Nickel (II) nitrate —> Ni(NO3)2

Parentheses () are optional when only one polyatomic ion is needed. Parentheses are needed if
there is more than one of the polyatomic ions!
* Ca3(AsO4)2 LiNO3 respective examples

Question 6

How do you go from chemical formula to name?
1. just the simple name for the formula
2. for elements with more than one possible charge

Answer 6

Just look at the sheet and write the name. It’s so easy lol. Remember that negative ions have “ide” at the end.

Use the charge on the anion to determine the charge of the cation. Generally transition metals have more than 1 charge. Then use roman numerals (II).

Example: Tin (Iv) carbonate

Question 7

How to name acids??
1. What are they?
2. How do you name them based on ide, ate, and ite?
3. How to go from word to formula?

Answer 7

Acids are ionic compounds that contain H +1 as their cation. Acids are named based on their anion.

• ide = hydro + ic acid. Hydrosulfuric acid. H2S
• ate = ic acid. Sulfuric acid. H2SO4
• ite = ous acid. Sulfurous acid. H2SO3

Use the reverse to determine the anion and balance out the charges for a neutral compounds. Look at examples:
H3P –> Hydrophosphoric acid “hydro + ic = ide so phosphide”.
IF IT STARTS WITH HYDRO, IT CANT HAVE OXYGEN.

Question 8

How to name molecular compounds?
1. What are molecular compounds??
2. What are the 10 prefixes needed for molecular compounds
3. How to name??
4. examples?

Answer 8

Covalently bonded molecules are made up of non metals only

1. mono
2. di
3. tri
4. tetra
5. penta
6. hexa
7. hepta
8. octa
9. nona
10. deca

Naming - Use the prefixes to indicate how many of each element is in one molecule. Change the ending on the second element to “ide”

a and o and o and o cannot be right next to each other.

N2O4 –> dinitrogen tetroxide not tetrAoxide
CO –> Carbon monoxide NOT monOoxide