Naming Simple Compounds - Chemistry - California State University

Naming Simple Compounds

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Ionic compounds

• consist of positive and negative ions.

• have attractions called ionic bonds between positively and negatively charged ions.

• have high melting and boiling points.

• are solid at room temperature.

Ionic Compounds


Salt is An Ionic Compound

Sodium chloride or “table salt” is an example of an ionic compound.

Copyright © 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings


Naming Ionic Compounds with Two Elements

To name a compound that contains two elements,

• identify the cationand anion.

• name the cation first followed by the name of the anion.


An ionic formula

• consists of positively and negatively charged ions.

• is neutral.

• has charge balance.total positive charge = total negative charge

The symbol of the metal is written first followed by the symbol of the nonmetal.

Binary Ionic Compounds Type (I)


Charge Balance In MgCl2

In MgCl2,

• a Mg atom loses two valence electrons.

• two Cl atoms each gain one electron.

• subscripts indicate the number of ions needed to give charge balance.



Charge Balance in Na2S

In Na2S.

• two Na atoms lose one valence electron each.

• one S atom gains two electrons.

• subscripts show the number of ions needed to give charge balance.



Guide to Writing Formulas from the Name



Writing Ionic Formulas from Charges

Charge balance is used to write the formula forsodium nitride, a compound containing Na+ and N3−.

Na+

3 Na+ + N3− = Na3NNa+

3(+1) + 1(3-) = 0


The balance of charges in Aluminum Oxide


Write the ionic formula of the compound with Ba2+ and Cl−.

• Write the symbols of the ions.Ba2+ Cl−

• Balance the charges. Ba2+ Cl− two Cl- needed

Cl−

• Write the ionic formula using a subscript 2 for two chloride ions that give charge balance.

BaCl2

Formula from Ionic Charges


Select the correct formula for each of the following ionic compounds.

A. Na+ and S2-

1) NaS 2) Na2S 3) NaS2

B. Al3+ and Cl-

1) AlCl3 2) AlCl 3) Al3Cl

C. Mg2+ and N3-

1) MgN 2) Mg2N3 3) Mg3N2

Learning Check


A. Na+ and S2-

2) Na2S check: 2Na+ + S2- = 2(1+) + 1(2-) = 0

B. Al3+ and Cl-1) AlCl3

check: Al3+ + Cl- = (3+) + 3(1-) = 0

C. Mg2+ and N3-

3) Mg3N2 check: 2Mg2+ +2N3- = 2(3+) + 2(3-) = 0

Solution


Useful relationships from the periodic table


Names of Some Common Ions



Formula Ions Namecation anion

NaCl Na+ Cl- sodium chloride

K2S K+ S2- potassium sulfide

MgO Mg2+ O2- magnesium oxide

CaI2 Ca2+ I- calcium iodide

Al2O3 Al3+ O2- aluminum oxide

Examples of Ionic Compounds with Two Elements


Learning Check

Write the formulas and names for compounds of the following ions:

Br− S2− N3−

Na+

Al3+


Solution

Br− S2− N3−

Na+

Al3+

NaBrsodium bromide

Na2Ssodium sulfide

Na3Nsodium nitride

AlBr3

aluminum bromide

Al2S3

aluminum sulfide

AlNaluminum nitride


Binary Ionic Compounds (Type II) Transition Metals form Positive Ions

Most transition metals and Group 4(14) metals form 2 or more positive ions.

Zn2+, Ag+, and Cd2+ form only one ion.


Metals that form more than One Cation

The name of metals with two or more positive ions(cations) use a Roman numeral to identify ionic charge.


Lead Pb2+ lead(II)Pb4+ lead(IV)


Naming Ionic Compounds with Variable Charge Metals



Naming Variable Charge Metals

Transition metals with two different ions use a Roman numeral after the name of the metal to indicate ionic charge.


Naming FeCl2

To name FeCl21. Determine the charge of the cation using the charge

of the anion (Cl-).Fe ion + 2 Cl- = Fe ion + 2- = 0Fe ion = 2+

2. Name the cation by the element name and add aRoman numeral in parenthesis to show its charge.

Fe2+ = iron(II)3. Write the anion with an ide ending.

FeCl2 = iron(II) chloride


Naming Cr2O3

To name Cr2O31. Determine the charge of cation from the anion (O2-).

2 Cr ions + 3 O2- = 02 Cr ions + 3 (2-) = 0 2 Cr ions - 6 = 02 Cr ions = +6 Cr ion = 3+ = Cr3+

2. Name the cation by the element name and add aRoman numeral in parenthesis to show its charge.

Cr3+ = chromium(III)3. Write the anion with an ide ending.

chromium(III) oxide = Cr2O3


Learning Check

Select the correct name for each.A. Fe2S3

1) iron sulfide2) iron(II) sulfide3) iron(III) sulfide

B. CuO1) copper oxide2) copper(I) oxide 3) copper(II) oxide


Solution

Select the correct name for each.A. Fe2S3

3) iron (III) sulfide Fe3+ S2-

B. CuO3) copper (II) oxide Cu2+ O2-


A polyatomic ion• is a group of atoms. • has an overall ionic charge.

Some examples of polyatomic ions areNH4

+ ammonium OH− hydroxide

NO3− nitrate NO2

− nitrite

CO32− carbonate PO4

3− phosphateHCO3

− hydrogen carbonate(bicarbonate)

Binary Compounds with Polyatomic Ions


Some Compounds with Polyatomic Ions



The names of common polyatomic anions

• end in ate.

NO3− nitrate PO4

3− phosphate• with one oxygen less end in ite.

NO2− nitrite PO3

3− phosphite• with hydrogen attached use the prefix hydrogen (or bi).

HCO3− hydrogen carbonate (bicarbonate)

HSO3− hydrogen sulfite (bisulfite)

Some Names of Polyatomic Ions


Names and Formulas of Common Polyatomic Ions


oxyanions


Names and Formulas of Common Polyatomic Ions



• The positive ion is named first followed by the name of the polyatomic ion.

NaNO3 sodium nitrate

K2SO4 potassium sulfate

Fe(HCO3)3 iron(III) bicarbonate

or iron(III) hydrogen carbonate

(NH4)3PO3 ammonium phosphite

Naming Compounds with Polyatomic Ions


Formation of Ionic Compounds


Some Compounds with Polyatomic Ions



Match each formula with the correct name.

A. MgS 1) magnesium sulfite MgSO3 2) magnesium sulfateMgSO4 3) magnesium sulfide

B. Ca(ClO3)2 1) calcium chlorateCaCl2 2) calcium chloriteCa(ClO2)2 3) calcium chloride

Learning Check


Match each formula with the correct name:

A. MgS 3) magnesium sulfideMgSO3 1) magnesium sulfite MgSO4 2) magnesium sulfate

B. Ca(ClO3)2 1) calcium chlorateCaCl2 3) calcium chlorideCa(ClO2)2 2) calcium chlorite

Solution


Learning Check

Name each of the following compounds:

A. Mg(NO3)2

B. Cu(ClO3)2

C. PbO2

D. Fe2(SO4)3

E. Ba3(PO3)2


Solution

Name each of the following compounds:

A. Mg(NO3)2 magnesium nitrate

B. Cu(ClO3)2 copper(II) chlorate

C. PbO2 lead(IV) oxide

D. Fe2(SO4)3 iron(III) sulfate

E. Ba3(PO3)2 barium phosphite


Writing Formulas with Polyatomic Ions

The formula of an ionic compound

• containing a polyatomic ion must have a charge balance that equals zero (0).

Na+ and NO3− NaNO3

• with two or more polyatomic ions has the polyatomic ions in parentheses.

Mg2+ and 2NO3− Mg(NO3)2

subscript 2 for charge balance


Select the correct formula for each.

A. aluminum nitrate

1) AlNO3 2) Al(NO)3 3) Al(NO3)3

B. copper(II) nitrate

1) CuNO3 2) Cu(NO3)2 3) Cu2(NO3)

C. iron(III) hydroxide

1) FeOH 2) Fe3OH 3) Fe(OH)3

D. tin(IV) hydroxide

1) Sn(OH)4 2) Sn(OH)2 3) Sn4(OH)

Learning Check


Select the correct formula for each.

A. aluminum nitrate 3) Al(NO3)3

B. copper(II) nitrate2) Cu(NO3)2

C. iron(III) hydroxide3) Fe(OH)3

D. tin(IV) hydroxide1) Sn(OH)4

Solution


Learning Check

Write the correct formula for each.

A. potassium bromateB. calcium carbonateC. sodium phosphateD. iron(III) oxideE. iron(II) nitrite


Solution

Write the correct formula for each.A. potassium bromate KBrO3

B. calcium carbonate CaCO3

C. sodium phosphate Na3PO4

D. iron(III) oxide Fe2O3

E. iron(II) nitrite Fe(NO2)2


Rules for Naming Ionic Compounds



Flowchart for Naming Ionic Compounds



Molecular vs. Ionic Compounds


Covalent Bonding


QUESTIONHypochlorous acid is related to the anion found in common household bleach. Which of the following is that common anion?

1. ClO4–

2. ClO3–

3. ClO2–

4. ClO–


QUESTIONWhich of the following provides the correct name for Ca(H2PO4)2?

1. Calcium dihydrogen phosphate2. Calcium (II) hydrogen phosphate3. Calcium di-dihydrogen phosphate4. Calcium (II) dihydrogen phosphate


Covalent bonds form

• when atoms share electrons to complete octets.

• between two nonmetal atoms.

• between nonmetal atoms from Groups 4A(14), 5A(15), 6A(16), and 7A(17).

Binary Covalent Compounds (Type III)


Naming Covalent Compounds

To name covalent compounds

• STEP 1: Name the first nonmetal as an element.

• STEP 2: Name the second nonmetal with an ideending.

• STEP 3: Use prefixes to indicate the number of atoms (subscript) of each element.

Table 2.6


What is the name of SO3?

1. The first nonmetal is S sulfur.

2. The second nonmetal is O named oxide.

3. The subscript 3 of O is shown as the prefix tri.SO3 sulfur trioxide

The subscript 1 (for S) or mono is understood.



Name P4S3.

1. The first nonmetal P is phosphorus. 2. The second nonmetal S is sulfide.3. The subscript 4 of P is shown as tetra.

The subscript 3 of S is shown as tri.

P4S3 tetraphosphorus trisulfide



Formulas and Names of Some Covalent Compounds



Select the correct name for each compound.A. SiCl4 1) silicon chloride

2) tetrasilicon chloride3) silicon tetrachloride

B. P2O5 1) phosphorus oxide2) phosphorus pentoxide3) diphosphorus pentoxide

C. Cl2O7 1) dichlorine heptoxide2) dichlorine oxide3) chlorine heptoxide

Learning Check


Select the correct name for each compound.

A. SiCl4 3) silicon tetrachlorideB. P2O5 3) diphosphorus pentoxideC. Cl2O7 1) dichlorine heptoxide

Solution


Write the name of each covalent compound.

CO _____________________

CO2 _____________________

PCl3 _____________________

CCl4 _____________________

N2O _____________________

Learning Check


Write the name of each covalent compound.

CO carbon monoxide

CO2 carbon dioxide

PCl3 phosphorus trichloride

CCl4 carbon tetrachloride

N2O dinitrogen monoxide

Solution


The prefixes in the name are used to write the formula.STEP 1: Write the symbols in the order of the elements in

the name. STEP 2: Write any prefixes as subscripts.

Example: Write the formula for carbon disulfide.STEP 1: Elements are C and SSTEP 2: No prefix for carbon means 1 C

Prefix di = 2Formula: CS2

Guide to Writing Formulas


Write the correct formula for each of the following.

A. phosphorus pentachloride

B. dinitrogen trioxide

C. sulfur hexafluoride

Learning Check


Write the correct formula for each of the following.

A. phosphorus pentachloride1 P penta = 5 Cl PCl5

B. dinitrogen trioxidedi = 2 N tri = 3 O N2O3

C. sulfur hexafluoride

1 S hexa = 6 F SF6

Solution


Learning Check

Identify each compound as ionic or covalent and give itscorrect name.

A. SO3

B. BaCl2C. (NH4)3PO4

D. Cu2CO3

E. N2O4


Binary Acids

If the anion does not contain oxygen:

HCl hydrogen chloride hydrochloric acid

HF hydrogen fluoride hydrofluoric acid

Acids produce H+ when dissolved in water.

They are compounds that ionize in water.

If the anion contain oxygen

Anion ends in-ate, the suffix –ic is added to the root name. Anion ends in –ite, the suffix –ous.

Naming Simple Compounds - Chemistry - California State University

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