# Ionic Compounds and Naming Chapter 4.10,4.11 and 5.

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Ionic Compounds and Naming Chapter 4.10,4.11 and 5

Combining Elements When we begin combining elements we make compounds. Two types ◦Non-metal and metal ◦Non-metal and non-metal Each type has unique physical and chemical properties Look at non-metal and metal in detail now and non-metal and non-metal later

Ionic compounds A metal and a non-metal combination make an ionic compound ◦Each element or polyatomic group is an ion ◦What makes an ion?  An ion is a charged particle (positive or negative)  Difference between protons and electrons in an element ◦ Ca vs Ca +2 (Ca +2 has 2 less electrons than Ca)

 The number of valence electrons determines the type of ion formed ◦ Trying to reach noble gas state  Lose or gain electrons to reach magic number 8 ◦ Valence electrons are known by group number  Main group elements only  These atoms follow a pattern down the column

Valence electrons vs charge

Practice How many valence electrons do the following elements have? What would their charge be? ◦KMgAlC ◦POBrAr ◦Do you see any pattern to the charges?  Metals make positive ions (cations)  Non-metals make negative electrons (anions)

Making ionic compounds First determine the charge on the cation and the anion. Then adjust the number of cations and anions you need to make the compound neutral. All ionic compounds are overall neutral; that is when you add up all the charges the sum is zero

Making ionic compounds NaCl is made with Na +1 and Cl -1 MgO is made with Mg +2 and O -2 Na 2 O is made with 2 Na +1 and O -2 MgCl 2 is made with Mg +2 and 2 Cl -1

Practice Combine K and F to make a neutral compound ◦K makes a K +1 ion ◦F makes a F -1 ion ◦Need one of each to make the ionic compound neutral ◦KF Put the following elements together to make ionic compounds Be and F Li and S Ba and N K and As Cs and C

Transition metals What about the elements in-between group II and III? ◦Called transition metals because they can make more than one positive charge ◦On our tables you can tell by the small black number above the symbol…..

Practice with transition metals Cu II and S W IV and O Pd II and N Cr III and Si

Polyatomic Ions Some ions are actually a group of elements combined together ◦Can not be broken apart ◦Act as one unit These are known as polyatomic ions ◦See handout

Naming Binary Compounds

We can easily name binary compounds both ionic and covalent (non-metals) ◦Non-metals and metals use type I and II ◦Non-metals and non-metals use type III

Naming Binary Ionic Compounds Type I ◦Metal bonded to non-metal ◦Metal always listed and named first  No changes in the metal name ◦Metals only make ONE ion (known as simple metals) ◦Anion is listed second  Use the root of the name and add –ide ◦ Hydrogen becomes hydride ◦ Halogens remove –ine and add –ide ◦ Oxide, nitride, sulfide ◦ NaCl is sodium chloride

Type II ◦use transition metals Cation is first again and anion is changed the same as type I The difference is that we need to designate the charge of the transition metal with a Roman Number USE THE ANION TO DETERMINE THE CHARGE OF THE CATION!!! CuO ◦Oxygen is -2 ◦The compound must be neutral ◦So the copper (Cu) must be +2 ◦The compound is named copper II oxide

Practice Name the following ionic compounds: CaFAlCl 3 MgI 2 CuBr 2 Al 2 O 3 CrCl 3 Fe 2 O 3 FeOFeCl 3 The number of atoms has no influence on the name for type I and II

Polyatomic Ions Polyatomic ions just use their name K 2 SO 4 would be potassium sulfate NH 4 NO 3 would be ammonium nitrate Co(NO 2 ) 2 (NH 4 ) 3 N

Type III ◦Non-metal to non-metals NUMBER OF ATOMS IS IMPORTANT FOR TYPE III Use prefixes to determine the number of atoms in the name Same naming scheme as type I  Use entire name for 1 st element  -ide for 2 nd  Add prefixes for multiple atoms ◦ Note: mono- is never used on 1 st element

Prefixes ◦1 – mono ◦2 – di ◦3- tri ◦4- tetra ◦5- penta ◦6- hexa ◦7- hepta ◦8- octa ◦9- nona ◦10- deca

Practice CCl 4 would be carbon tetrachloride N 2 O 2 would be dinitrogen dioxide PCl 5 P 4 O 6 N 2 O 5 SF 6 CONO 2

Naming Acids Acids are a special group of binary compounds and have their own naming rules. All acids begin with H and are dissolved in water Acids without oxygen ◦Use root of anion and add –ic and acid ◦HCl is hydrochloric acid Acids with oxygen ◦-ite becomes –ous ◦-ate becomes –ic ◦H 2 SO 3 is sulfurous acid ◦H 2 SO 4 is sulfuric acid

Naming acids If the anion ends in –ide ◦Start with hydro ◦Use the root of the anion ◦Add –ic acid to the end If the anion ends in –ate ◦NO HYDRO ◦Use the root or slightly more and add –ic acid If the anion ends in –ite ◦NO HYDRO ◦Use the root or slightly more and add –ous acid

Practice Name these acids HF HNO 3 H 3 PO 4

Reversing the process Write the formulas from these names: Nitric acid Potassium sulfide Sodium carbonate Dinitrogen pentoxide