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Writing and Naming Ionic compounds (criss cross method). Rule 1: Write the symbol of the metallic element first. Beryllium combines with Chlorine. +. 2. -. 1. Be Cl. Rule 2: Place the combining capacity of one element as a subscript of the other element.
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Writing and Naming Ionic compounds (criss cross method)
Rule 1: Write the symbol of the metallic element first. Beryllium combines with Chlorine + 2 - 1 Be Cl Rule 2: Place the combiningcapacityof one element as a subscript of the other element.
Rule 3:Leave subscripts with a value of 1 out. Be Cl2 1 The formula becomes BeCl2
Rule 4: Reduce the subscripts when necessary by the greatest common factor. Magnesium combines with Sulfur + 2 - 2 Mg S S Mg MgS
Potassium combines with chlorine • Magnesium combines with bromine • Calcium combines with oxygen • Sodium combines with nitrogen • Lithium combines with sulfur KCl MgBr2 CaO Na3N Li2S
Naming Ionic Compounds Two general rules: 1. Write the full name of the metal ionfirst. 2. Name the non-metal iondropping the last part of the name and adding the suffix “ide”. The naming of compounds is monitored and updated by the International Union of Pure and Applied Chemistry (IUPAC).
Potassium combines with chlorine • Magnesium combines with bromine • Calcium combines with oxygen • Sodium combines with nitrogen • Lithium combines with sulfur KCl - Potassium Chloride MgBr2 - Magnesium Bromide CaO - Calcium Oxide Na3N - Sodium Nitride Lithium Sulfide
The metal is named first and the non-metal is named second. • The non-metal always changes end to an “ide”. • Crisscross method - combining capacity of one is the subscript of the other. • Reduce the numbers is possible (2, 4 = 1, 2) • Total e- given by metals equals • total e- taken by the non-metals
Transition metals can give away different numbers of electrons. To avoid confusion: Brackets are used to show how many electrons the Transition metal is giving away.
Roman numerals tell combining capacity of Transition metals. I 1 II 2 III 3 IV 4 V 5 VI 6 VII 7 VIII 8 IX 9 X 10
Iron (II) chloride Iron (III) chloride + 2 - + 3 - 1 1 Fe Cl Fe Cl FeCl2 FeCl3
Write the formula for cobalt (III) oxide: + 3 - 2 Co O Co2O3
Write the Name: + - 1 Co Br CoBr 3 Cobalt Bromide (III)
Write the name of the ionic compound: +4 -2 + - 1 Pb O PbO 2 lead oxide (IV)
Write the name: +2 -2 1 1 + - Cu S CuS copper sulfide (II)
3. Lead (II) combines with sulfur Pb S +2 -2 Pb S lead (II) sulfide
WRITING COMPOUNDS: • Write the symbol of the metallic element first. • Place the combiningcapacityof one element as a subscript of the other element. • Leave subscripts with a value of 1 out. • NAMING COMPOUNDS: • Write the full name of the metal ionfirst. • Name the non-metal iondropping the last • part of the name and adding the suffix “ide”. Brackets are used to show how many electrons the Transition metal is giving away.