Chemical Names and Formulas

Molecules A molecule is the smallest electrically neutral unit of a substance that still has the properties of the substance. 1. Monatomic - consist as a single atom (Ex: Noble gases) 2. Diatomic molecule - 7 exist in nature “BrINCl HOF” 3. Triatomic molecule ( Ex: O 3 - ozone) He (means 2) atoms Br 2 I 2 N 2 Cl 2 H 2 O 2 F 2

Chemical Formula: s hows the kinds and numbers of atoms in the smallest representative unit of the substance (formula unit) REMEMBER!!!! H – Element symbol always begins with a capital letter Na – If symbol has two letters, the second letter is always lowercase H2OH2OH2O2H2O2 What’s the difference between these two formulas? When you change the subscripts the formula no longer represents that compound.

Chemical Formulas How to read formulas: H 2 O = 2 hydrogen atoms 1 oxygen atom Ca(OH) 2 – Number outside the parenthesis distributes to inside the parenthesis 1 calcium atom 2 oxygen atoms 2 hydrogen atoms

Explain the following: MgCl 2 – What elements are present? How many? Mg - Cl - Pb(NO 3 ) 2 – What elements are present? How many? Pb - N - O

Ionic Charges of Representative Elements 1A2A3A4A5A6A7A8A Li + Na + K + Rb + Cs + Be 2+ Mg 2+ Ca 2+ Sr 2+ Ba 2+ Al 3+ N 3- P 3- As 3- O 2- S 2- Se 2- F - Cl - Br - I -

Oxidation Numbers – how many electrons an atom would gain or lose to follow the octet rule (also called its charges)

Charges of Transition Metals These transition metals have more than one charge: Cr 2+ or 3+ Cu + or 2+ Mn 2+ or 3+ Sn 2+ or 4+ Fe 2+ or 3+ Pb 2+ or 4+ Co 2+ or 3+ Ni 2+ or 3 + Hg 1+ or 2+ Au 1+ or 3 + Sc 2+ or 3+ Hg 1+ or 2 +

I. Writing Formulas for Binary Ionic Compounds Rules: 1.Write symbol and charge for both cation and anion. 2.Crisscross charges, drop the charge and write as subscripts. 3.CHECK!! The formula must be in the lowest possible ratio. The cation is always written first!

Example Problems Write formulas for these compounds: calcium iodide Ca I +2- CaI 2 21

O -2 Tin (IV) oxide Sn +4 Sn 2 O 4 SnO 2 4 2

Aluminum sulfide Al S Al 2 S White Board Practice

Be O BeO Beryllium Oxide 2 2 Be 2 O 2

II. Naming Binary Ionic Compounds 1.) Use the name of the cation. ****Use Roman Numerals if Transition Metal. 2.) Name the anion and change ending to -ide.

SnS 2 Naming Binary Ionic Compounds Use Roman Numerals Tin(IV) Find Sn Where is it located? -2 Sulfide +4 +2

B.) CuBr 2 WHITE BOARD practice problems A.) KCl C.) AlF 3 D.) MgO E.) MnI 2

Al +3 P -3

1.) K + S -2 White Board Practice

2.) Al +3 I -

3.) Ag + O -2

4.) Ni +2 O -2

5.) Pb +4 O -2

Polyatomic Ions Tightly bound groups of atoms that behave as a unit and carry a charge. Ammonium NH 4 + Cyanide CN - Sulfite SO 3 2- Examples:

III. Writing Formulas for Ternary Ionic Compounds A. Contain a polyatomic ion B. Same rules as for binary ionic compounds. One addition – Use parenthesis if there is more than one polyatomic ion Ex: Calcium Hydroxide Ca 2+ OH - CaOH 2 Ca(OH) 2

Boron acetate B 3+ C 2 H 3 O 2 -1 Magnesium Dichromate Mg +2 Cr 2 O 7 -2

White Board Practice Problems Write formulas for the following ternary ionic compounds: a.Calcium Carbonate b.Barium Nitrite c.Potassium Sulfate d.Magnesium Phosphate

IV. Naming Ternary Ionic Compounds Same rules as for naming binary ionic compounds: –Name the cation ***Use a Roman numeral if necessary –Name the anion (change ending to –ide) Polyatomic ions will stay the same!!

White Board Practice Problems: Name the following ternary ionic compounds: a.NaCN b.NH 4 ClO c.Li 2 SO 3 d.CaC 2 O 4 e.Al(OH) 3 f.Sn 3 (PO 4 ) 2

Ionic Compounds- Polyatomic Ions Left Side of Spiral ClOHSO 4 PO 4 NO 3 Zn +2 NH 4 K Ca Fe

V. Rules for Naming Covalent Compounds 1. Prefixes are used to show how many atoms of each element are present in the compound Prefixes used for Naming Binary Covalent Compounds

2. Second element is written with an – ide ending. ***All binary compounds, both ionic and covalent end in –ide. 3. The vowel at the end of the prefix is dropped when the name of the element begins with the same vowel. Ex: monoxide, not monooxide Rules for Naming Covalent Compounds

4. Mono is omitted if there is just a single atom on the first element in the name. Ex: CO 2 carbon dioxide not monocarbon dioxide Rules for Naming Covalent Compounds

Naming Binary Covalent Compounds 1.) CO 2.) SO 2 3.) N 2 O 4.) CCl 4 5.) N 2 O 5 6.) NO 4 7.) OF 2

Writing Formulas for Binary Covalent Compounds Write the formulas for the following compounds. 1. carbon monochloride 2. nonacarbon tetrachloride 3. heptabromine dioxide 4. phosphorus trichloride 5. octanitrogen pentafluoride

Ionic vs. Covalent Are the following compounds ionic or covalent? b. Sodium chloride c. CuSO 4 d. CO e. Lithium hydroxide f. dinitrogen tetraoxide g. FeS h. Cobalt (III) chloride i. H 2 S j. PF 3 a. H 2 O

Naming Acids HClhydrochloric acid H 2 SO 4 sulfuric acid HNO 3 nitric acid HC 2 H 3 O 2 acetic acid H 3 PO 4 phosphoric acid H 2 CO 3 carbonic acid

ECHS Relay Challenge 1.) How many atoms of fluorine are present in CF 4 ? 2.) How many atoms of carbon are present in CF 4 ? 3.) What is the formula for carbon monoxide? 4.)What is the formula for lithium chloride? 5.) What is the formula for the compound formed by iron (II) and carbonate ions? 6.) What is the formula for aluminum hydroxide? 7.) What is the formula for lead (IV) oxide? 8.) What is the formula for magnesium nitrate? 9.) What is the name of the compound: NH 3 ? CCl 4 ? 10.) What is the cation in iron (II) oxide? 11.) What is the name of the compound N 2 O 2 ? H 2 O 2 ? 12.) What is the formula for sulfur trioxide? 13.) What is the formula for dinitrogen tetrafluroide? 14. )What prefix is used to represent ten? 15.) How do you know a compound is covalent when looking at the chemical formula? 16.) Using the ion pairs listed, write the correct chemical formula that the ions would form: a. Cr +3 I - = b. Cu +2 O -2 = c. Li + S -2 = 17.) What is the oxidation number for iron (II) in iron (II) oxide? 18. Write the names for the compound FeO and Fe 2 O 3. Justify why the names you wrote are correct. 19.) What are the seven diatomic elements? 20.) What is the name of the compound Si 2 Br 6 ? 21.) Write the formula for diboron hexahydride. 22.) Write the formula for oxygen gas.