Section 3 Writing & Naming Compounds CHAPTER 19 Section 3 Writing & Naming Compounds

TLW write and name binary ionic compounds. OBJECTIVES TLW write and name binary ionic compounds. TLW write and name polyatomic ionic compounds.

Materials Needed Today Periodic table  for oxidation numbers Polyatomic Ions Reference sheet

BINARY = 2 elements POLYATOMIC = more than 2 elements

Write the name of the 1st element NAMING BINARY IONIC NaCl  Sodium Chloride Write the name of the 1st element Write the root of the 2nd element and add “-ide”

Try a couple… MgO Magnesium Oxide LiBr Lithium Bromide

Sodium Chloride Na is 1+ and Cl is 1- 1+ and 1- = 0  Stability NaCl WRITING BINARY IONIC Refer to Oxidation Numbers Sodium Chloride Na is 1+ and Cl is 1- 1+ and 1- = 0  Stability NaCl

Try another… CaF2  Calcium Fluoride (subscripts??? Where did those come from???) Calcium has an oxidation number of 2+ Fluorine has an oxidation number of 1- So, “cross” the oxidation numbers to make subscripts Ca +2 and F -1  CaF2

A couple more… Calcium Nitride Ca3N2 Barium Phosphide Ba3P2

PRACTICE ACTIVITY Get up, move around, and “bond” with your classmates.

NAMING POLYATOMIC IONIC CaCO3 Write the name of the 1st element Use the Chart to write the name of the Polyatomic Ion Calcium Carbonate

Try a couple… HSO4 Hydrogen Sulfate K2CO3 Potassium Carbonate

WRITING POLYATOMIC IONIC Calcium Hydroxide Write the 1st element  Ca Use the chart for the Polyatomic Ion Hydroxide  OH Don’t forget oxidation numbers = subscripts!!! Ca2+ and OH 1- “cross” the oxidation numbers to make subscripts Ca(OH)2 don’t forget parenthesis for the polyatomic

Practice a couple… Magnesium Nitrate Mg 2+ [NO3]- …chart Mg(NO3)2

Always an exception… (discuss this more tomorrow) Some elements may have more than 1 oxidation number See Table 2 on page 588 Copper (I) and Copper (II) Iron (II) and Iron (III) Chromium (II) and Chromium (III) Lead (II) and Lead (IV) All are + ions, so they will be 1st in the compound

PRACTICE TLW write and name binary ionic compounds. TLW write and name polyatomic ionic compounds. …tomorrow…write and name binary covalent…and practice, practice, practice…review, review, review Balancing chemical equations