Guidelines for Writing Formulas & Naming Compounds

Chemical Names & Formulas Name:_______________________________________Period:______Date:_______

I. REVIEWING IONS 1. _________________= atom or a group of bonded atoms with a positive or negative charge. 2. ____________________ = ion with a POSITIVE (+) charge. a) Forms when an atom LOSES one or more _____________________electrons b) Ex: Be+2 forms b/c beryllium ________________ ________valence electrons •

Be has the following electron configuration: 1s22s2 o How many VALENCE electrons does Be have? ƒ

•

How many protons and electrons does a Be atom have? o _____

•

________ valence electrons protons and _____ electrons

How many protons and electrons does Be+2 have? o _______ protons and ______ electrons. o Creating a _______ ion

3. ____________________ = ion with a NEGATIVE (-) charge. a) Forms when an atom GAINS one or more _________________ electrons b) Ex: F-1 forms b/c fluorine _______________ ______ valence electron •

F has the following electron configuration: 1s22s22p5 o How many VALENCE electrons does F have? ƒ

_______ valence electrons

• How many protons and electrons does the F atom have? o ______ protons and _______ electrons • How many protons and electrons does F-1 have? o ______ protons and ______ electrons. o Creating a _____ ion 4. ___________________________________ = ion formed from only ONE atom a) Ex: Na+1, Ca+2, N-3, F-1 1

b) Note: All monatomic _________________ end in –ide • Ex: atom = oxygen; ion = ______________________________ • Ex: atom = chlorine; ion = _____________________________ • Ex: atom = sulfur; ion = ______________________________ 5. ____________________________________________ = ion formed from two or more atoms bonded together with a charge. a) Ex: SO4-2, Hg2+2, OH-1, CN-1 6. Classify the following as monatomic anion, monatomic cation, polyatomic anion, or polyatomic cation. a) Li +1 = __________________________________________ b) O2-2 = _________________________________________ c) NH4+1 = ________________________________________ d) S-2 = __________________________________________ 7. REMEMBER- Rules For Assigning Ion Charges:

8. Roman Numerals ƒ

Sometimes an atom is able to give away a various number of electrons and be stable

ƒ

The Roman numerals tell how many __________________ have been given away and that will be the ______________________charge ƒ

Ex: iron (II) and iron (III)

ƒ

Fe

+2

and Fe

+3

2

II. WRITING IONIC FORMULAS 1. _________________________________are formed by two ions of opposite charge (_____________ are + and ____________ are -) and that they are held together by a relatively weak attraction between the ions. 2. KEY IDEA-Ionic Compounds: ƒ

Usually _____________________ and _________________elements combine

ƒ

Are __________________________compounds 1. The simplest whole number ____________________ between the cation & anion creates the ionic formula 2. The net charge is _____________, forming a ____________ ionic compound. •

Ex: MgCl2 - _____ magnesium ion : _____chloride ions

•

Ex: KBr - _____ potassium ion : _____ bromide ion

•

Ex: Ca3(PO4)2 - ____ calcium ions : ____ phosphate ions

3. Care must be taken that subscripts are correct ƒ

Ex: NaCl vs. CaCl2

4. Why does the chlorine have a subscript of “2” in one chemical formula but not in the

other? ƒ

Look at the ion charges! o Sodium is ________ and chloride is ________ • A +1 and a -1 charge form an ionic compound with a zero charge! o Calcium is ________ and chloride is ________ • NOW _____________________ ions are needed in order to form a neutral compound

5. All IONIC compounds are ________________. So the algebraic sum of the charges has to equal _____________! 3

ƒ

Ex: Aluminum sulfate has the following chemical formula: Al2(SO4)3 A chemical formula for this ionic compound shows that ______ Al+3 ions and

•

_____SO4-2 ions are needed in order to form a neutral compound. 6. Examples of Forming Ionic Compounds ™ Example #1: Write a formula for aluminum chloride. •

What are the charges of the ions? ƒ

•

What do the charges mean? ƒ ƒ

•

________ and ________ Aluminum _______________ electrons Chlorine ________________ electron

How is aluminum chloride formed? ƒ

Use electron-dot formulas to illustrate the formation of ionic bonds involving Al and Cl.

ƒ

It takes ______ chlorine atoms to gain the ______ electrons that ______ aluminum atom can donate.

ƒ

When this transfer occurs, 1 ____________________ will be formed and three _______________________ will be formed.

ƒ

These particles will all be held together by the _____________ electrostatic charges. •

The formula is ___________.

9 Think of writing an ionic formula as looking for a lowest possible

ratio of positive and negative ions that need to combine in order to form a neutral compound!

4

™ Example #2: Write a formula for sodium sulfide. •

What are the charges of the ions? ƒ

•

________ and __________

What is the ratio or combination that these ions must form in order to form a NEUTRAL compound? ƒ

• 7.

_____sodium ions and ______sulfide ion

Write the formula for sodium sulfide: _________________

Rules For Writing Ionic Formulas: 1) The subscript 1 is understood when ______ subscript is present and is not written 2) Use parentheses around __________________________ when adding additional subscripts. ™ PROTECT POLYATOMICS WITH PARENTHESES!! 3) Write the symbol for the positive ion (_________________) first, following by the negative ion (_________________) 4) Determine the simplest whole number ___________ between the cation & anion o Use the “criss-cross” method- the NUMBERS of the positive and negative charges can be “crossed” over to give the correct subscripts to the opposite ion. ƒ

Ex #1: What is the formula of the compound formed by the ions of magnesium and bromine? o Ions = Mg+2 and Br-1 o Formula = Mg Br2

ƒ

Ex #2: Aluminum sulfide (use the “criss-cross” method) o Ions = ____________________ o Formula = ________________

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Ex #3: Magnesium oxide o Ions = _________________________ o Formula = ____________________ ƒ

We must reduce this to the lowest terms!

ƒ

The final answer is ____________ 5

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Ex #4:Sodium peroxide •

polyatomic- NO parentheses and NO reduction o Ions = _______________________ o Formula = ____________________ ƒ

NO REDUCTION -This is the correct formula for this compound since

we cannot reduce a subscript which is already set as a part of the original ion!

ƒ

Ex #5: Copper II sulfate •

polyatomic- NO parentheses and reduction o Ions = __________________________ o Formula = _______________

ƒ

Ex #6: Calcium nitrate •

polyatomic- PROTECT with PARENTHESES

•

You cannot alter the ____________________ that come with polyatomic ions, we use ______________________________! o Ions = ____________________ o Formula = _____________________

9 Note: NEVER use _____________________ around _______________ ions (Na, Li, Fe, Cu, etc). Only ______________________ ions (SO4, MnO4, NH4, PO3, etc.) will ever require the use of parentheses.

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II. NAMING IONIC COMPOUNDS: 1. Rules:

a. Determine the name of the cation & anion that is present ƒ

________________________ charged ion name comes 1st

ƒ

_________________________charged ion name comes 2nd - Ex: AgCl = ________________________________________ - Ex: Ba3(PO4)2 = ____________________________________

b. Ions with ____________than one charge, you have to figure out the charge and use the correct _________________________! ƒ

ƒ

Always use the _________________________ to figure out the correct cation

Ex: FeO •

Determine the charge of the anion (neg. ion) o Oxide’s charge is________

ƒ

•

So Fe has to have a _______charge because FeO is a NEUTRAL compound!

•

Ions have to be: ________and ____________

•

So it is ________________________

Ex: Cr2(SO4)3 •

Determine the charge of the anion (neg. ion) o Sulfate’s charge is _____ and you have 3 ions for a total charge of ___ for the anions.

•

So the _____ Cr ions have to have a total charge of _____ since Cr2(SO4)3 is a NEUTRAL compound.

•

Ions have to be: ________and __________

•

So it is _______________________________________

7

III. WRITING MOLECULAR FORMULAS 1) Chemical formula for a molecular compound is called a molecular formula 2) _________________________ = formula showing the types and numbers of atoms combined in a single molecule of a molecular compound ƒ

Molecular compounds are usually __________________

3. ______________ tell you what the ___________________ will be! ƒ

Ex: Carbon monoxideÆ ________

ƒ

Ex: Carbon dioxideÆ

ƒ

Ex: Dinitrogen trioxide Æ __________

________

Prefixes: 1 2 3 4 5

MonoDiTriTetraPenta-

6 7 8 9 10

HexaHeptaOctaNonDeca-

IV. NAMING MOLECULAR COMPOUNDS 1. Rules for naming molecular compounds: a. A prefix is used with the name of the FIRST element ONLY if there is more than one atom of that element is present. b. The second element is named by combining a prefix and changing the ending to ____ ƒ

Ex: NO

is called ___________________________

ƒ

Ex: N20 is called ___________________________

2. Hints to use when molecular and ionic compounds are on the same worksheet/test: ƒ

Determine if the compound is molecular or ionic.

ƒ

Molecular compounds ONLY contain ___________________.

ƒ

Ionic compounds ONLY contain ______________ and _________________.

ƒ

Compounds that contain ammonium ion (NH4+) are ____________compounds.

ƒ

Remember that there is an ion “dichromate”. So dichromate would be part of an ___________________ compound! 8

Ion Review Worksheet 1) What is the difference between anions and cations? Explain how these ions are formed.

2) What is the difference between a monatomic ion and a polyatomic ion?

3) Classify each of the following as a monatomic anion, monatomic cation, polyatomic anion, or a polyatomic cation. a) O-2 = _________________________________________ b) NH4+1 = _________________________________________ c) SO3 -2 = _________________________________________ d) Na +1 = _________________________________________ e) Hg2 +2 = _________________________________________ 4) What is the ending of all monatomic anions? _____________________ 5) Determine the name of the ion that would form from the following atoms. a) Atom = phosphorus; ion = ____________________________ b) Atom = bromine; ion = ____________________________ c) Atom = oxygen; ion = _____________________________ 6) Some ions have a Roman numeral with their symbol. For example, lead II. How are the Roman numeral and charge related?

7) What elements are present for most ionic compounds? _________________________________ 8) What is the ratio between cation(s) & anion(s) in the following ionic compounds? a) K3PO4 = _________ potassium ion(s) : ________ phosphate ion(s) b) LiCl = _________ lithium ion(s) : ________ chloride ion(s) c) Ba3(PO3)2 = _________ barium ion(s) : ________ phosphite ion(s) d) Ag2SO4 = _________silver ion(s) : ________ sulfate ion(s) 9

9) Place the ionic charges for the following groups on the Periodic Table: group 1, group 2, group 312, group 13, group 14, group 15, group 16, group 17 and group 18.

10)Suppose magnesium formed an ion. a) What is the charge of a magnesium ion? __________________ b) How many electrons and protons does a magnesium ion have?

11)Suppose bromine formed an ion. a) What is the charge of a bromine ion? ___________________ b) What is the name of this ion? ____________________________ c) How many electrons and protons does a bromide ion have?

12)Fluorine has the following electron configuration: 1s2 2s2 2p5 a) How many valence electrons are present? ___________ b) What ion will fluorine form? ______________ • Explain why using the electron configuration.

c) What is the name of this ion? _________________________ 13)Sodium has the following electron configuration: 1s2 2s2 2p63s1 a) How many valence electrons are present? ___________ b) What ion will sodium form? ______________ • Explain why using the electron configuration.

c) What is the name of this ion? _________________________ 10

Writing IONIC Formulas (Criss-Cross Method) 9 Directions: Write the ionic formulas of the following compounds.

1) Sodium chloride____________

5) Iron III chloride__________

2) Sodium carbonate__________

6) Iron III carbonate_________

3) Sodium hydroxide__________

7) Iron III hydroxide__________

4) Sodium phosphate__________

8) Iron III phosphate__________

9) Ammonium chloride________ 10) Ammonium carbonate________ 11) Ammonium hydroxide________ 12) Ammonium phosphate________

22) Calcium chloride__________ 23) Calcium carbonate_________ 24) Calcium hydroxide________ 25) Calcium phosphate_________

13) Tin IV chloride___________ 14) Tin IV carbonate____________ 15) Tin IV hydroxide___________ 16) Tin IV phosphate___________

17) Aluminum sulfate ______________ 18) Lithium sulfide _______________ 19) Copper II fluoride _______________ 20) Magnesium nitrate _______________ 21) Ammonium oxide_______________

1) Barium phosphate ______________

6) Calcium sulfate _________________

2) Aluminum sulfide _______________

7) Magnesium hydroxide ___________

3) Iron II bromide _______________

8) Chromium III oxide______________

4) Potassium nitride _______________

9) Copper I phosphite ________________

5) Ammonium sulfide_______________

10) Tin IV oxide ________________

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Naming IONIC Compounds Name the following ionic compounds: 1. CaCO3 ________________________________________________ 2. Pb(CH3COO)2 ___________________________________________ 3. FeSO4 ________________________________________________ 4. LiBr __________________________________________________ 5. MgCl2 _________________________________________________ 6. FeCl3 _________________________________________________ 7. Zn3(PO4)2 _______________________________________________ 8. NH4NO3 _______________________________________________ 9. Al(OH)3 ________________________________________________ 10. PbSO3 _________________________________________________ 11. NaClO3 _________________________________________________ 12. Fe2O3 __________________________________________________ 13. (NH4)3PO4 _______________________________________________ 14. NaHSO4 ________________________________________________ 15. CuCl2 __________________________________________________ 16. Mg(NO2)2 ________________________________________________ 17. CuSO4 __________________________________________________ 18. NaHCO3 _________________________________________________ 19. NiBr2 ___________________________________________________ 20. Ba(NO3)2 _________________________________________________ 21. ZnSO4__________________________________________________ 22. AuCl ___________________________________________________ 23. KMnO4 __________________________________________________

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Naming MOLECULAR Compounds Name the following molecular compounds: 1. PCl3

_____________________________________

2. CO

_____________________________________

3. SO2

_____________________________________

4. P2O3

_____________________________________

5. N2O

_____________________________________

6. SCl2

_____________________________________

7. N2O3

_____________________________________

8. CF4

_____________________________________

9. N2O4

_____________________________________

10. S2F10

_____________________________________

Writing MOLECULAR Formulas Write the molecular formulas:

1. Carbon dioxide

_________________

2. Phosphorous pentachloride

_________________

3. Nitrogen trihydride

_________________

4. Sulfur hexachloride

_________________

5. Diphosphorous pentoxide

_________________

6. Carbon tetrachloride

_________________

7. Sulfur dioxide

_________________

8. Phosphorus tribromide

_________________

9. Chlorine trifluoride

_________________

10. Sulfur dibromide

_________________

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Naming Compounds Worksheet 9 Hint: find molecular compounds FIRST and use prefixes!! 1. NH4I ___________________________

CaO2_____________________

2. Fe2O3 ___________________________

N2O3_____________________

3. K2CO3 ___________________________

Hg(NO3)2____________________

4. FeI2___________________________

Li2CO3_____________________

5. PbNO3__________________________

NaNO3_____________________

6. NF3___________________________

Ag2S_____________________

7. Mn(OH)2 ___________________________

Hg2Cl2_____________________

8. Mg3(PO4)2___________________________ KNO3_____________________ 9. Fe(CN)2 ___________________________

N2S3_____________________

10. Al2O3_____________________________

Na3PO4_____________________

11. Ca3(PO4)2 ___________________________

ZnCl2____________________

12. Al2(CO3)3 ___________________________ NH4F_____________________ 13. K2O ___________________________

NaHCO3_____________________

14. FeSO4 ___________________________

NH4NO3_____________________

15. CCl4___________________________

PBr3_____________________

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Writing Formulas Worksheet 9 Hint: find molecular compounds FIRST and use prefix rules!! 1. Barium permanganate _______________

Chromium II phosphite____________

2. Chromium II nitrate _______________

Mercury II sulfide_______________

3. Sodium fluoride_______________

Copper II nitride________________

4. Lithium carbonate _______________

Tin II fluoride__________________

5. Magnesium sulfate_______________

Tin IV bromide__________________

6. Calcium nitrite_______________

Carbon tetrachloride______________

7. Barium bromide_______________

Phosphorus triodide_______________

8. Chromium III acetate_______________

Dinitrogen hexafluoride____________

9. Carbon monoxide_______________

Chromium II hydroxide____________

10. Iron II sulfite_______________

Ammonium carbonate_____________

11. Nickel II phosphate

Barium hydroxide_______________

_______________

12. Copper I chloride _______________

Barium chromate_______________

13. Silver chromate_______________

Calcium sulfate_________________

14. Zinc hydroxide_______________

Lead II carbonate_______________

15. Mercury II nitrate_______________

Magnesium dichromate_______________

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More PRACTICE W.F & N.C.!!! Name:________________________________________________Period:________

Naming Compounds:

Writing Formulas:

1. CuCO3 _________________________________

oxygen difluoride_______________

2. Cu(OH)2_________________________________

potassium dichromate_______________

3. Al2(SO4)3_________________________________

silver nitrate_____________________

4. Fe(NO3)2_________________________________

magnesium sulfite_______________

5. (NH4)2SO4 _________________________________

lead II chromate__________________

6. BaCl2_________________________________

sodium hydrogen sulfate __________

7. Na2CO3_________________________________

carbon dioxide___________________

8. N2H6_________________________________

Phosphorus trichloride____________

9. MgSO4_________________________________

silver sulfide_____________________

10. P2O5_________________________________

aluminum hydroxide_____________

11. NaHCO3_________________________________

Carbon disulfide ________________

12. HgO_________________________________

iron III bromide__________________

13. N2O3_________________________________

lead II sulfide____________________

14. Na2O2_________________________________

potassium fluoride_______________

15. HgCl2_________________________________

calcium peroxide_________________ 16

Review W.F & N.C. Worksheet 1) _________________ are positive ions b/c they have ____________one or more valence electrons. 2) _________________ are negative ions b/c they have ____________one or more valence electrons. 3) ______________________________ are ions formed from a single atom. 4) ______________________________ are ions formed from a group of bonded atoms. 5) Determine the name of the ion that would form from the following atom. a) Atom = sulfur; ion = ____________________________ 6) What is the ratio between cation(s) & anion(s) in the following ionic compound? a) Na2SO4 = _________ sodium ion(s) : ________ sulfate ion(s) 7) Classify each of the following as a monatomic anion, monatomic cation, polyatomic anion, or a polyatomic cation. a) O2-2 = _________________________________________ b) K +1 = _________________________________________ c) MnO4 -1 = _______________________________________ 8) Suppose sodium formed an ion. a) What is the charge of a sodium ion? __________________ b) How many protons does a sodium ion have? ______ and electrons? ___________ 9) What elements make up ionic compounds?___________________________________________ 10) What elements make up molecular compounds?_______________________________________ 11) Identify if the following compound is ionic (I) or molecular (M) and then write the formula or name the compound. _____a. N2O5 ___________________

_____f. Carbon tetrachloride___________

_____b. FeCl2 ___________________

_____g. Magnesium hydroxide _____________

_____c. SF6 ____________________

_____h. Dinitrogen tetroxide _______________

_____d. NH4Cl _________________

_____i. Ammonium phosphate______________

_____e. PbCO3 __________________

_____j. Tin (IV) sulfate ___________________

Naming Compounds:

Writing Formulas:

1. SiCl4 _________________________________

dinitrogen trifluoride_______________

2. Pb3(PO4)2_________________________________

ammonium oxide_______________

3. Al(MnO4)3_________________________________

lithium cyanide____________________

4. Fe(NO3)2_________________________________

disulfur decaflouride_______________

5. (NH4)2SO4 _________________________________

aluminum dichromate_____________ 17

Unit Learning Map( 6 days): Writing Formulas & Naming Compounds

Mrs. Hostetter

Class: Academic Chemistry A - Grade 11 PA Standard: 3.4A : Explain the formation of compounds and their resulting properties using bonding theories (ionic and covalent). Recognize formulas for simple inorganic compounds.

Optional Instructional Tools:

Unit Essential Question(s):

How do scientists represent compounds?

Concept Ionic Compounds

Concept

Lesson Essential Questions:

How are ionic compounds named and written?

How are molecular compounds named and written?

Criss-Cross Method Ionic Formula Ionic compound Cation Anion Polyatomic ion Monatomic ion

Concept

Concept

Molecular Compounds

Lesson Essential Questions:

Vocabulary:

Guided Notes Lab Materials: ƒ Bond w/ a classmate ƒ Ionic Lab

Vocabulary:

Lesson Essential Questions:

Vocabulary:

Lesson Essential Questions:

Vocabulary:

Molecular formula Molecular compounds

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Writing Formulas & Naming Compounds Vocabulary: 1) “criss-cross” method = the positive and negative charges can be “crossed” over to give the subscripts to the opposite ion. •

Ex: What is the formula of the compound formed by the ions of magnesium and bromine? o Ions = Mg+2 and Br-1 o Formula = Mg Br2

2) Ionic compounds = compounds formed by an attraction between cations and anions ƒ Ionic compounds are usually a metal and a nonmetal 3) Ionic Formula = ions will combine in such a ratio that there will be a net charge of zero, forming a neutral compound. 4) Monatomic ion = ion formed from a single atom; Ex: S-2 and Fe+2 5) Polyatomic ion = a group of bonded atoms with a charge; Ex: NH4+ and NO3− 6) Cation = positive ion b/c the parent atom lost valence electron(s) 7) Anion= negative ion b/c the parent atom gained valence electron(s) 8) Molecular formula = Chemical formula for a molecular compound 9) Molecular compounds = formula showing the types and numbers of atoms combined in a single molecule of a molecular compound ƒ Molecular compounds are usually 2 nonmetals

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Guidelines for Writing Formulas & Naming Compounds: Guideline for WRITING IONIC FORMULAS: 1) Ionic compounds are usually created by joining a metal and a nonmetal 2) The subscript 1 is understood when NO subscript is present and is not written 3) Use parentheses around polyatomic ions when adding additional subscripts. ™ PROTECT POLYATOMICS WITH PARENTHESES!! 4) Write the symbol for the positive ion (cation) first, following by the negative ion (anion) 5) Determine the simplest whole number ratio between the cation & anion o Use the “criss-cross” method- the NUMBERS of the positive and negative charges can be “crossed” over to give the correct subscripts to the opposite ion.

Guideline FOR NAMING IONIC COMPOUNDS: 1) Positively charged ion name comes first 2) Negatively charged ion name comes second 3) Ions with more than one charge state, you have to figure out the charge and use the correct roman numerals! ƒ Use the anions charge to determine what cation is present!

Guideline for WRITING MOLECULAR FORMULAS: 1) Prefixes tell you what the subscript will be! ƒ Ex: Carbon monoxideÆ CO ƒ Ex: Carbon dioxideÆ CO2

Guideline for NAMING MOLECULAR COMPOUNDS: 1. A prefix is used with the name of the first element (one that is less electronegative) ONLY if more than one atom of that element is present. ƒ Ex: NO is called nitrogen monoxide ƒ Ex: N20 is called dinitrogen monoxide 2. The second element is named by combining (a) a prefix if more than one compound can be formed by the two elements (b) the root of the name of the second element, and (c) the ending –ide 3. Hints to use when molecular and ionic compounds are on the same worksheet/test: ƒ Determine if the compound is molecular or ionic. ƒ Molecular compounds ONLY contain NONMETALS. ƒ Ionic compounds ONLY contain METALS and NONMETALS. ƒ Compounds that contain ammonium ion (NH4+) are IONIC compounds.

ƒ

Remember that there is an ion “dichromate”. So dichromate would be part of an IONIC compound! 20