# Drill12/1/14  Rank the following elements by increasing atomic radius: Al, C, K, O  Rank the following elements by increasing electronegativity: O, Ne,

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Drill12/1/14  Rank the following elements by increasing atomic radius: Al, C, K, O  Rank the following elements by increasing electronegativity: O, Ne, S, Al

Drill12/1/14  Rank the following elements by increasing atomic radius: O, C, Al, K  Rank the following elements by increasing electronegativity: Ne, Al, S, O

Agenda  Quest – Pd 4B and 4A  Notes on Ionic and Covalent Cpds (all classes)

Announcement  Lab next class. Must wear appropriate clothing and shoes.

Oxidation Numbers

 Used to indicate the distribution of electrons among the bonded atoms in a molecule (covalent bond) or a polyatomic ion.

How are they used?  Naming compounds  Writing formulas  Balancing chemical equations

Oxidation Numbers (review)  Remember, most atoms strive to have eight valence electrons (some are satisfied with only two)  Atoms will form various bonds by gaining, losing, or sharing electrons, in order to satisfy the Octet Rule

Oxidation Numbers  An atom’s electron configuration is used to determine how many electrons need to be gained, lost, or shared  Example – Na (11 electrons)  1s 2 2s 2 2p 6 3s 1 – 1 valence electron  In order for Na to have eight valence electrons, would it be easier for it to gain 7 electrons, or lose 1?  Losing 1 is easier

Oxidation Numbers  When Na loses an electron it becomes an Na +1 ion  1s 2 2s 2 2p 6 3s 1 becomes…  1s 2 2s 2 2p 6 – 8 valence electrons  Na carries a +1 charge because it has lost an electron, and it now has more positively charged protons than negatively charged electrons

Oxidation Numbers  Another Example – Fluorine (9 electrons)  1s 2 2s 2 2p 5 – 7 valence electrons  In order for F to have eight valence electrons, would it be easier for it to gain 1 electron, or lose 7?  Gaining 1 is easier

Oxidation Numbers  When F gains an electron it becomes an F -1 ion  1s 2 2s 2 2p 5 becomes…  1s 2 2s 2 2p 6 – 8 valence electrons  F carries a -1 charge because it has gained an electron, and it now has more negatively charged electrons than positively charged protons

Oxidation Numbers  There is a fairly consistent pattern to oxidation numbers with families  Transition Metals and Inner Transition Metals usually have a varying number of valence electrons  Some don’t – Zn +2, Cd +2, Sc +2, Ag +1

Complete with the people in your row. Oxidation Number Practice

 List the oxidation number for the following families – Alkali metals – Alkaline earth metals – Halogens – Noble Gases  Write the oxidation numbers for the following elements  Aluminum  Sulfur  Cesium  Iodine  Xenon  Strontium  Tin  Selenium

No Drill12/3/14  You are responsible for memorizing 15 polyatomic ions for the next test. They are on my webpage. Best way to memorize is to make flashcards.

Objectives  SWBAT name binary ionic compounds.  SWBAT write formulas for binary ionic compounds.

Bond Type by Electronegativity Electronegativity Difference Bond Type <0.3nonpolar covalent Between 0.3 & 1.7polar covalent >1.7ionic

Bond Polarity and Electronegativity  Nonpolar covalent bond – a bond in which the bonding electrons are shared equally by the bonded atoms –Example: Cl-Cl  Polar covalent bond – a bond in which the bonded atoms have an unequal attraction for the shared electrons –Example: H-Cl

Agenda  Writing Formulas/Naming Ionic Cpds: –Notes

Writing Formulas/Naming Ionic Compounds

Definition  An ionic compound is composed of positive (cation) and negative ions (anion) that are combined so that the number of positive and negative charges are equal.

Think About It….  You already know how to name a binary ionic compound, but you may not know it yet.  Think about table salt. What is its chemical name? What rule seems to be in effect when naming it? How can we apply this rule to the naming of all simple ionic compounds?

How might we name these compounds?  NaBr  KF  BaCl 2  NaI  MgO

Naming an Ionic Compound  To name a simple binary ionic compound, simply change the ending of the second ion to –ide –For example, NaCl isn’t sodium chlorine, but sodium chloride instead

Writing the Formula for an Ionic Compound  You already know how!  However, there is an easier way to do it.

Criss-Cross Method 1. Do the sum of the charges for the two ions = 0? 2. If not, use the criss-cross method 3. The charge on one ion becomes the subscript on the other (Cross the charges of the ions).

Practice Problem  Using the criss-cross method, determine the formula for aluminum oxide.

Answer You do not need to write the charges for the ions in the formula.

Practice Problem  Using the criss-cross method, determine the formula for calcium sulfide.

Practice Problem  Using the criss-cross method, determine the formula for potassium phosphide.

Polyatomic Ions and Roman Numerals Chapter 7

Types of Ions  Monatomic Ion – an ion consisting of “one-atom” –For example, K +1  Polyatomic Ion – an ion made from more than one atom –For example, NH 4 +1

Naming an Ionic Compound that Contains a Polyatomic Ion  Ionic compounds containing polyatomic ions are named in a very similar way as those containing monatomic ions –Name the polyatomic ion exactly as it appears on the ion sheet –Example: Na 2 SO 4 is sodium sulfate

Writing the Formula for an Ionic Compound that Contains a Polyatomic Ion  Use the criss-cross method to write the formula for ionic compounds containing polyatomic ions  When the criss cross method forces you to add a subscript to a polyatomic ion which already has a subscript, then you must use parentheses to separate the subscripts

Example Problem  Using the criss-cross method, write the formula for ammonium oxide.

Answer  (NH 4 ) 2 O

Example Problem  Using the criss-cross method, write the formula for sodium nitrate.

Example Problem  Using the criss-cross method, write the formula for magnesium nitrite.

Answer  Mg(NO 2 ) 2

Roman Numerals  Some metals have varying charges (usually transition metals).  When an element commonly has more than one charge, you must use Roman numerals to name it.

Example  There are 2 common ions for iron: Fe +2 and Fe +3  Fe 2 O 3 would be named iron(III) oxide –The (III) corresponds to the charge on the metal iron  FeO would be named iron(II) oxide –The (II) corresponds to the charge on the metal iron

Drill 12/5 and 6/2014  Using the criss-cross method, write the formula for lithium nitride.  Name the following compounds: –(a) Li 3 P –(b) SeI 2 –(c) SrF 2

Answers  Li 3 N  (a) lithium phosphide  (b) selenium diiodide  (c) strontium fluoride

Drill 12/5/14  If tin (Sn) has common charges of +2 and +4, then how would we name the following compound? SnF 2 SnF 2

Homework – due today  Pd – 3 and 4A – Lab  Pd 4B – Criss Cross Method WS

Naming Molecular (Covalent) Compounds  Simple molecular compounds containing 2 atoms are named with prefixes  The prefixes indicate the number of atoms in the molecule

Prefixes Mono- 1Nona- 9 Di- 2Deca- 10 Tri- 3 Tetra- 4 Penta- 5 Hexa- 6 Hepta- 7 Octa- 8

Note  Normally the prefix mono- is not used (carbon monoxide is an exception)

Example  Name the following compound: CO 2

More Practice  Name the following compounds: –SO 2 –SO 3 –CO –P 2 O 5 –OF 2 –P 4 O 10 –N 2 O 4

Assignments – due next class  7-1 and 7-3 Practice Problems  Ionic and Covalent Formula Writing and Naming WS  Naming Molecular Compounds

Drill12/7/14  Naming Molecular Compounds

HW Due  7-1 and 7-3 Practice Problems (all)  Ionic and Covalent Formula Writing and Naming WS (4B)  Pd. 4A and 4B – Covalent and Ionic Cpds Lab

Announcement  Quiz on Wednesday or Thursday  Abstract due on Friday

Agenda  Finish notes on Covalent Cpds  Naming Chemical Cpd Lab

Lab Procedure  Place your well over the top of a piece of white paper.  Place 1 drop of each solution in the well.  Record the following in each square: observation, chem formula and name.

Objectives  SWBAT write formulas for ionic compounds containing polyatomic ions.  SWBAT recognize when to use Roman numerals to name ionic compounds.

Drill #19 12/6/11  Using the criss-cross method, write the formula for lithium nitride.  Name the following compounds: –(a) Li 3 P –(b) SrF 2

Assignment  Complete Criss Cross Method WS

Answers  Li 3 N  (a) lithium phosphide  (b) strontium fluoride

Drill #12 12/12/12 & 12/13/12  When writing ionic compounds, which element is written first?  The element with the positive charge (cation or metal)

Naming Ionic and Molecular Compounds

Objectives  SWBAT name simple ionic and molecular compounds.  SWBAT use roman numerals to name ionic compounds containing metals that can have more than one charge.

Drill  Make a list of 6 common prefixes.

Review  A simple ionic compound is made up of a positive __________ ion and a negative ____________ ion.

Naming Ionic Compounds  Ionic compounds are named just as they are read, except that the anion end is changed to –ide.  For example, NaCl is not called sodium chlorine, but sodium chloride instead.

Examples  Name the following compounds: –MgI 2 –RbBr –SrS –CaO –Li 3 P –NaF

Review  What is a transition metal?

Metals With More Than One Charge  On your “Ion Sheet,” you can see that some metals can have more than one charge. –For example, copper can have a 1+ or 2+ charge  If an ion can have more than one charge, you must specify its charge in the formula name using ROMAN NUMERALS

Example  Name this compound: CuBr  This compound would be named Copper(I) Bromide since copper is existing in the 1+ state  CuBr 2 would be named Copper(II) Bromide since copper is in the 2+ state

More Practice  Name the following ionic compounds: –FeO –Cu 3 N 2 –Fe 2 O 3 –Cu 3 P –CuCl –FeCl 2

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