Names and Formulas for Ionic Compounds Part 1

Types of ions Monatomic ion Polyatomic ion ion with one atom Mg2+ magnesium ion Cl- chloride ion Polyatomic ion ion with more than one atom NH4+ ammonium NO3- nitrate

Ionic Compound Marriage Metals are like men Nonmetals are like woman Typically who changes their last name?

Naming Ca”t”ions Monatomic cation name stays the same Sodium, Na goes to sodium ion, Na+ Calcium, Ca goes to calcium ion, Ca 2+ Polyatomic cation - look up in chart NH4+ ammonium

Naming Anions The name changes in a monatomic anion The ending for a monatomic anion is ______ide (like a bride changes her last name) chlorine, Cl goes to chloride ion, Cl- Fluorine, F goes to fluoride ion, F- Polyatomic anion look up in chart OH- hydroxide SO42- sulfate

Question Time Given the neutral atom, give the charge and name of the monatomic ion that will form. (Look at periodic table group numbers for help.) Na Cl Mg S P Na+ sodium cation Cl- chloride anion Mg2+ magnesium cation S2- sulfide anion P3- phosphide anion

Naming ionic compounds Name the cation first and then the anion second (+ then -) Example: CsF Monatomic cations use the element name Cs+ = cesium ion Monatomic anions – change the ending to ide F - = fluoride ion Name: cesium fluoride

Will these form an Ionic Compound? If so what will the compound name be? Mg Al Al S Mg O Na N C S No two metals Yes aluminum sulfide Yes magnesium oxide Yes sodium nitride No two non-metals

Formula Unit Formula Unit—the smallest whole number ratio of ions in a compound NaCl versus Na2Cl2 Correct: Sodium Chloride NaCl Which is the correct formula unit for sodium chloride? Why?

What will the formula be? In ionic compounds, we must balance charges to form a neutral compound To do that, we “crisscross the charges” Always reduce to get the formula unit Ca + N Ca2+ + N3- Ca3 N2 Both have a total charge of 6 (3 Ca2+ = +6; 2 N3- = -6)

Practice Given the following elements, predict the formula. (hint first identify the ion charge) K, Br Ca, Cl Li, S Mg, N Ba, P K+, Br- KBr Ca2+, Cl- CaCl2 Li+, S2- Li2S Mg2+, N3- Mg3N2 Ba2+, P3- Ba3P2

Names and Formulas for Ionic Compounds Part 2

Other Types of ions (page 5) Polyatomic ion ion with more than one atom NH4+ ammonium NO3- nitrate

Naming Ca”t”ions (page 5) Polyatomic cation - look up in chart NH4+ ammonium

Naming Anions (page 6) Polyatomic anion look up in chart OH- hydroxide SO42- sulfate

Question Time (page 6) Name of the ion. (Look at the back of periodic table.) NH4+ OH- SO3- SO42- CN- ammonium cation hydroxide anion sulfite anion sulfate anion cyanide anion

Ionic Compound Marriage Metals are like men (potassium) Nonmetals are like woman and sometimes they have children too (chlorite) K + ClO2 - = KClO2 +

Naming ionic compounds (not in NT) Name the cation first and then the anion second (+ then -) Example 1: NaCN Monatomic cations use the element name Na+ = sodium ion Polyatomic anions – look up CN - = cyanide Name: sodium cyanide

Naming ionic compounds (not in NT) Name the cation first and then the anion second (+ then -) Example 2: NH4CN Polyatomic cations-look up NH4+ = ammonium ion Polyatomic anions – look up CN - = cyanide Name: ammonium cyanide

Formula Unit with Polyatomic ions (middle of page 7) Sometimes you will need to use more than one polyatomic ion to balance a charge. If so, you need to put it in parenthesis (like a package) and use a subscript for the multiple number Ex: Mg2+ and NO3- These charges do not balance so we must crisscross them Mg1(NO3)2 (we don’t need the 1) Mg (NO3)2

Practice (do at the bottom of page 7) Given the following, predict the formula. (hint first identify the ion charges) K, BrO3- Ca, CO32- Li, SO42- Mg, NO3- Ba, PO43-

Naming and Formulas: Transition Metals-Part 3

Transition Metal Ions Metals form cations Some transition metals only have one ionic charge Silver (Ag+), Cadmium (Cd2+), Zinc (Zn2+) Some transition metals can take on more than one charge. Copper (Cu+, Cu2+) Charge is determined from the number of electrons lost Transition metals form compounds the same way all cations do, which enables us to find the formula units in a similar fashion.

Naming Transition Metal Ions If a transition metal has more than one charge, the charge is written as a Roman numeral in parenthesis Some metals need a middle name Fe (iron) has more than one charge: 2+ and 3+ Fe2+ iron(II) Fe3+ iron(III) If the transition metal only has one charge, no Roman numeral is needed

Naming Ionic Compounds with Transition Metals (not in NT, copy on bottom of page 7) Given: Fe2O3 First find the charges of the ions Then name the cation followed by the anion Iron(III) oxide Try this one: Fe3P2 the charge on iron is a 2+ iron(II) phosphide Ions: O2- and Fe3+ What do we call the cation? What do we call the anion?

Question Time(not in NT, copy on bottom of page 7) Identify the charge on the transition metal: copper (II) nitrate gold (I) chromate Name the compound: FeO Zn(OH)2 CoPO4 2+ 1+ iron (II) oxide zinc hydroxide cobalt (III) phosphate