Section 7.1 Chemical Names and Formulas Note Taking Tips: 1. You do NOT need to write every word; get the high points so that what you recall later makes sense to you. 2. Abbreviate when u can!

Section 7.1 Naming Ions Atoms are electrically neutral. Because there is the same number of protons (+) and electrons (-). Ions are atoms, or groups of atoms, with a charge (positive or negative) They have different numbers of protons and electrons. Only electrons can move, and ions are made by gaining or losing electrons.

Section 7.1 Naming Ions 1. Monatomic ion – an ion formed from a single atom 11. Polyatomic ion – an ion made of two or more atoms acting as a single unit with a charge *See Periodic Table of Ions (handout)

K1+ Ca2+ A Cation is… A positive ion. Formed by losing electrons. Metals can lose electrons Charge written as superscript on rt. Has lost one electron (no name change for positive ions = potassium ion) K1+ Ca2+ Has lost two electrons = calcium ion

A Cation Charge is… When metals in Groups 1, 2 lose electrons, they form cations with positive charges equal to their group number

F1- O2- An Anion is… A negative ion. Has gained electrons. Nonmetals can gain electrons. F1- Has gained one electron (-ide is new ending = fluoride) O2- Gained two electrons (oxide)

An Anion Charge is… The charge of any ion of a nonmetal in group 15-17 is determined by subtracting 18 from the group number.

Charge of Transition Metals… The charge of cations of many transition metal ions must be determined from the number of electrons lost.

Ion High School

Predicting Ionic Charges Group 1: Lose 1 electron to form 1+ ions H1+ Li1+ Na1+ K1+ Rb1+

Predicting Ionic Charges Group 2: Loses 2 electrons to form 2+ ions Be2+ Mg2+ Ca2+ Sr2+ Ba2+

Predicting Ionic Charges Group 13: Loses 3 electrons to form 3+ ions B3+ Al3+ Ga3+

Predicting Ionic Charges Group 14: Neither! Group 14 elements rarely form ions (except ones below metalloid line = Ge, Sn, Pb) Do they lose 4 electrons or gain 4 electrons?

Predicting Ionic Charges Nitride Gains 3 electrons to form 3- ions Group 15: P3- Phosphide As3- Arsenide

Predicting Ionic Charges Oxide Gains 2 electrons to form 2- ions Group 16: S2- Sulfide Se2- Selenide

Predicting Ionic Charges Gains 1 electron to form 1- ions Group 17: F1- Fluoride Br1- Bromide Cl1- Chloride I1- Iodide

Predicting Ionic Charges Group 18: Stable noble gases do not form ions!

Predicting Ionic Charges Transition elements: Many have more than one possible oxidation state. Note the use of Roman numerals to show charges Iron (II) = Fe2+ Iron (III) = Fe3+

Naming cations Two methods can clarify when more than one charge is possible: 12. Stock system – uses roman numerals in parenthesis to indicate the numerical value 13. Classical method – uses root word with suffixes (-ous, -ic) Does not give true value

Naming cations Classical method – uses root word with suffixes (-ous, -ic) -ous = lower charge - ic = higher charge Does not give true value

Naming cations We will use the Stock system. Cation - if the charge is always the same (like in the Group A metals) just write the name of the metal. Transition metals can have more than one type of charge. Indicate their charge as a roman numeral in parenthesis after the name of the metal (Table 9.2, p.255)

Predicting Ionic Charges Some of the post-transition elements also have more than one possible oxidation state. Tin (II) = Sn2+ Lead (II) = Pb2+ Tin (IV) = Sn4+ Lead (IV) = Pb 4+

Predicting Ionic Charges Some transition elements have only one possible oxidation state, such as these three: Transition Metals: Silver = Ag1+ Zinc = Zn2+ Cadmium = Cd2+

Exceptions: Some of the transition metals have only one ionic charge: Do not need to use roman numerals for these: Silver is always 1+ (Ag1+) Cadmium and Zinc are always 2+ (Cd2+ and Zn2+)

Practice by naming these cations: Al3+ Fe3+ Pb2+ Li1+ sodium ion calcium ion aluminum ion iron (III) ion lead (II) ion lithium ion

Write symbols for these: Potassium ion Magnesium ion Copper (II) ion Chromium (VI) ion Barium ion Mercury (II) ion K1+ Mg2+ Cu2+ Cr6+ Ba2+ Hg2+

Naming Anions Change the monatomic element ending to – ide F1- a Fluorine atom will become a Fluoride ion.

Practice by naming these: Cl1- N3- Br1- O2- chloride nitride bromide oxide

Write symbols for these: Sulfide ion Iodide ion Phosphide ion S2- I1- P3-

Polyatomic ions are… - groups of atoms that stay together and have an overall charge, and one name. Most polyatomic anions end in –ate or -ite Acetate: C2H3O21- Nitrate: NO31- Nitrite: NO21- Permanganate: MnO41- Exceptions: Hydroxide: OH1- and Cyanide: CN1-?

Have your Periodic Table of Ions Phosphate: PO43- Phosphite: PO33- Ammonium: NH41+ Sulfate: SO42- Sulfite: SO32- Carbonate: CO32- Chromate: CrO42- Dichromate: Cr2O72- (One of the few positive polyatomic ions) If the polyatomic ion begins with H, then combine the word hydrogen with the other polyatomic ion present: H+ + CO32- → HCO3- hydrogen + carbonate → hydrogen carbonate ion

Important Information: 7.1 Practice Problems Chapter 7 Vocabulary 1-10 Chapter 7 Notes: A-C Activity: Naming Ionic Compounds due Wed 7.1 Reading Guide due Friday

Sec 7.1 Naming and Writing Formulas for Ionic Compound 2. Binary compound – composed of two elements and can be either ionic or molecular (covalent) Ex: FeCl3 Al2S3

Chapter 7 Notes To name any binary ionic compound, place the cation name first, followed by the anion name.

A. Writing Formulas for Ionic Compound Example: Barium nitrate (note the 2 word name) 1. Write the formula for the cation followed by anion, including CHARGES ( ) Ba2+ NO3- 2. If the cation has ( ), the number in parenthesis is the charge. 2 Now balanced. 3. Use the criss-cross method to balance charges. Not balanced! = Ba(NO3)2 4. Use parentheses if you need more than one of a polyatomic ion. 5. reduce subscripts to lowest whole number ratio

Writing Ionic Compound Formulas Example: Ammonium sulfate (note the 2 word name) 1. Write the formula for the cation followed by anion, including CHARGES ( ) NH4+ SO42- 2. If the cation has ( ), the number in parenthesis is the charge. 2 Now balanced. 3. Use the criss-cross method to balance charges. Not balanced! = (NH4)2SO4 4. Use parentheses if you need more than one of a polyatomic ion. 5. reduce subscripts to lowest whole number ratio

Writing Ionic Compound Formulas Example: Iron (III) chloride (note the 2 word name) 1. Write the formula for the cation followed by anion, including CHARGES Fe3+ Cl- 2. If the cation has ( ), the number in parenthesis is the charge. 3 Now balanced. Not balanced! 3. Use the criss-cross method to balance charges. = FeCl3 4. Use parentheses if you need more than one of a polyatomic ion. 5. reduce subscripts to lowest whole number ratio

Writing Ionic Compound Formulas Example: Aluminum sulfide (note the 2 word name) 1. Write the formula for the cation followed by anion, including CHARGES Al3+ S2- 2. If the cation has ( ), the number in parenthesis is the charge. 2 3 Now balanced. 3. Use the criss-cross method to balance charges. Not balanced! = Al2S3 4. Use parentheses if you need more than one of a polyatomic ion. 5. reduce subscripts to lowest whole number ratio

Writing Ionic Compound Formulas Example: Zinc hydroxide (note the 2 word name) 1. Write the formula for the cation followed by anion, including CHARGES ( ) Zn2+ OH- 2. If the cation has ( ), the number in parenthesis is the charge. 2 Now balanced. 3. Use the criss-cross method to balance charges. Not balanced! = Zn(OH)2 4. Use parentheses if you need more than one of a polyatomic ion. 5. reduce subscripts to lowest whole number ratio

B. Naming Ionic Compounds 1. Name the cation first, then anion 2. Monatomic cation = name of the element Ex. Ca2+ = calcium ion 3. transition and post-transition cations have ( ) if more than one charge (number in parenthesis is their charge). 4. Monatomic anion (off periodic table) = root + -ide Ex. Cl- = chloride CaCl2 = calcium chloride 5. Most polyatomic anions end in -ate or –ite (exception: cyanide and hydroxide)

Naming Ionic Compounds (Metals with multiple oxidation states) some metals can form more than one charge (usually the transition metals) use a Roman numeral in their name: PbCl2 – use the anion to find the charge on the cation (chloride is always 1-) Pb2+ is the lead (II) cation PbCl2 = lead (II) chloride

C. Things to remember about Ionic Cmpds If cations have ( ), the number in parenthesis is their charge. If anions end in -ide they are probably off the periodic table (Monoatomic) If anion ends in -ate or –ite, then it is polyatomic

Practice Problems a) Ba2+, S2- b) Li+, O2- c) Ca2+, N3- d) Cu2+, I- barium sulfide Li2O lithium oxide Ca3N2 calcium nitride CuI2 copper (II) iodide

Practice Problems a) sodium iodide b) stannous chloride c) potassium sulfide d) calcium iodide Na+, I- NaI Sn2+, Cl- SnCl2 K+, S2- K2S Ca2+, I- CaI2

7.1 Practice Problems p. 211: 1-2 p. 213: 1-2 p. 215: 1-2 Finish a set and turn to Appendix E page (R121) to check and correct your answers.. Self-correct.