IONS AND IONIC COMPOUNDS MONATOMIC IONS are atoms with a positive or negative charge.MONATOMIC IONS are atoms with a positive or negative charge. Taking away an electron from an atom gives a CATION with a positive chargeTaking away an electron from an atom gives a CATION with a positive charge Adding an electron to an atom gives an ANION with a negative charge.Adding an electron to an atom gives an ANION with a negative charge.

PREDICTING ION CHARGES In general metals (Mg) lose electrons ---> cationsmetals (Mg) lose electrons ---> cations –Charge = group number nonmetals (F) gain electrons ---> anionsnonmetals (F) gain electrons ---> anions –Charge = group number -8

Charges on Common Ions By losing or gaining e-, atom has same number of e-’s as nearest Group 8A atom.

METALS M ---> n e- + M n+ where n = periodic group Na + sodium ion Mg 2+ magnesium ion Al 3+ aluminum ion Transition metals -->M 2+ or M 3+ are common Fe 2+ iron(II) ion Fe 3+ iron(III) ion See Table 9.2 page 255

Transition Elements Charges of 2+ and 3+ are common Roman numeral indicates the charge of the ion Classical Name – suffixes indicate charge (sort of) –ous means less –ic means more See Table 9.2 page 255 

NONMETALSNONMETALS NONMETAL + n e > X n- where n = 8 - Group no. C 4-,carbide N 3-, nitride O 2-, oxide S 2-, sulfide F -, fluoride Cl -, chloride Group 7AGroup 6A Group 4A Group 5A Br -, bromide I -, iodide

Predicting Charges on Monatomic Ions

POLYATOMIC IONS Groups of atoms with a charge.Groups of atoms with a charge. Names end in –ite or –ateNames end in –ite or –ate –ite means less –ate means more MEMORIZE the names and formulas in Table 9.3 page 257. 

Polyatomic Ions HNO 3 nitric acid NO 3 - nitrate ion

Polyatomic Ions NH 4 + ammonium ion One of the few common polyatomic cations

Polyatomic Ions CO 3 2- carbonate ion HCO 3 - bicarbonate ion hydrogen carbonate

PO 4 3- phosphate ion CH 3 CO 2 - acetate ion Polyatomic Ions

SO 4 2- sulfate ion SO 3 2- sulfite ion Polyatomic Ions

Naming Binary Ionic Compounds Binary compounds are composed of two elements, a metal and a non- metal. Place the name of the cation first and then the name of the anion. –Remember the –ide suffix. chlorideSodium The cation The anion

Writing formulas for Binary Ionic Compounds Write the symbol of the cation and the anion (include the charge) Add whatever subscripts are needed to balance the charge Use the criss-cross method –The charge of one ion becomes the subscript of the other. Don’t forget to reduce to the empirical formula.

Naming Ternary Ionic Compounds Ternary compounds are composed of three or more elements. Place the name of the cation first and then the name of the anion. Often end in –ite and -ate Strontium The cation sulfate The polyatomic ion. Don’t change the name

Writing formulas for Ternary Ionic Compounds Write the symbol of the cation and the anion (include the charge) Add whatever subscripts are needed to balance the charge Use parentheses when the compound contains more than one polyatomic ion Use the criss-cross method

Naming Binary Molecular Compounds Binary compounds are composed of two elements, two non-metals. The name identifies the elements and how many of each atom there is in the compound. Name the elements in the order they appear in the formula. Use prefixes to indicate the number of each kind of atom. Omit mono- when the name has only one atom of the first element. Use the suffix –ide for the name of the second element.

9.3 Naming Binary Molecular Compounds

Name these compounds! PBr 3 CrBr 3 N 2 O Na 2 O Cl 4 PbI 4 P 2 O 3 Fe 2 O 3

Writing formulas for Binary Molecular Compounds Use the prefixes in the name to determine the subscript of each element in the formula. Phosphorus pentafluoride

Naming Acids Ionic compounds with unique properties Contain one or more hydrogen atoms and produce H + ions when dissolved in water 1.When the name of the anion ends in –ide, the acid name begins with hydro-. The stem of the anion has the suffix –ic and is followed by the word acid. HCl hydrogen chloride acid name – hydrochloric acid 2.When the anion name ends in –ite, the acid name is the stem of the anion with the suffix –ous, followed by the word acid. H 2 SO 3 hydrogen sulfite Acid name – sulfurous acid 3.When the anion name ends in –ate, the acid name is the stem of the anion with suffix –ic followed by the word acid. HNO 3 hydrogen nitrate Acid name – nitric acid

Naming Bases Ionic compounds with unique properties Produce OH - ions when dissolved in water Named the same as other ionic compounds –Name of the cation followed by the anion.