Naming Compounds Writing Formulas Chapter 5

Systematic Naming l There are too many compounds to remember the names of them all. l Compound is made of two or more elements. l Put together atoms. l Name should tell us how many and what type of atoms.

Periodic Table l More than a list of elements. l Put in columns because of similar properties. l Each column is called a group.

2A 1A 3A4A 5A 6A 7A 0 Representative elements l The group A elements l The tall columns

Metals

Transition metals l The Group B elements

Non-metals l Dull l Brittle l Nonconductors - insulators

Metalloids or Semimetals l Properties of both l Semiconductors

Atoms and ions l Atoms are electrically neutral. l Same number of protons and electrons. l Ions are atoms, or groups of atoms, with a charge. l Different numbers of protons and electrons. l Only electrons can move. l Gain or lose electrons.

Anion l A negative ion. l Has gained electrons. l Non metals can gain electrons. l Charge is written as a superscript on the right. F 1- Has gained one electron O 2- Has gained two electrons

Cations l Positive ions. l Formed by losing electrons. l More protons than electrons. l Metals form cations. K 1+ Has lost one electron Ca 2+ Has lost two electrons

Two Types of Compounds  Molecular compounds l Made of molecules. l Made by joining nonmetal atoms together into molecules.

Two Types of Compounds  Ionic Compounds l Made of cations and anions. l Metals and nonmetals. l The electrons lost by the cation are gained by the anion. l The cation and anions surround each other. l Smallest piece is a FORMULA UNIT.

Two Types of Compounds Smallest piece Melting Point State Types of elements Formula UnitMolecule Metal and Nonmetal Nonmetals solid Solid, liquid or gas High >300ºCLow <300ºC IonicMolecular

Chemical Formulas l Shows the kind and number of atoms in the smallest piece of a substance. l Molecular formula- number and kinds of atoms in a molecule. l CO 2 l C 6 H 12 O 6

Formula Unit l The smallest whole number ratio of atoms in an ionic compound. l Ions surround each other so you can’t say which is hooked to which.

Charges on ions l For most of Group A elements, location on the Periodic Table can tell what kind of ion they form l Elements in the same group have similar properties. l Including the charge when they are ions.

Charge in groups 1A, 2A and 3A is the group number in 5A, 6A and 7A are different.

Can also use electron dots l If it has a few it loses them l If it has many, it gains enough for octet K + Al 3+ F - N 3-

What about the others? l We have to figure those out some other way. l More on this later.

Naming ions l Cation- if the charge is always the same (Group A) just write the name of the metal. l Most transition metals can have more than one type of charge. l Indicate the charge with Roman numerals in parenthesis. l Co 2+ Cobalt(II) ion

Naming ions l A few, like silver, zinc and cadmium only form one kind of ion l Don’t get roman numerals l Ag + silver ion l Zn 2+ zinc ion l Cd 2+ cadmium ion

Name these l Na 1+ Sodium ion l Ca 2+ Calcium ion l Al 3+ Aluminum ion l Fe 3+ Iron(III) ion l Fe 2+ Iron(II) ion l Li 1+ Lithium ion l Pb 2+ Lead(II) ion

Write Formulas for these l Potassium ion K 1+ l Magnesium ion Mg 2+ l Copper(II) ion Cu 2+ l Chromium(VI) ion Cr 6+ l Barium ion Ba 2+ l Mercury(II) ion Hg 2+

Naming Anions l Anions are always the same. l Change the element ending to – ide l F 1- Fluorine

Naming Anions l Anions are always the same. l Change the element ending to – ide l F 1- Fluorin

Naming Anions l Anions are always the same l Change the element ending to – ide l F 1- Fluori

Naming Anions l Anions are always the same l Change the element ending to – ide l F 1- Fluor

Naming Anions l Anions are always the same l Change the element ending to – ide l F 1- Fluori

Naming Anions l Anions are always the same l Change the element ending to – ide l F 1- Fluorid

Naming Anions l Anions are always the same l Change the element ending to – ide l F 1- Fluoride

Naming Anions l Anions are always the same l Change the element ending to – ide l F 1- Fluoride ion

Name these l Cl 1- Chloride ion l N 3- Nitride ion l Br 1- Bromide ion l O 2- Oxide ion l Ga 3+ Gallium ion

Write these l Sulfide ionS 2- l Iodide ionI 1- l Phosphide ionP 3- l Strontium ionSr 2+

Polyatomic ions l Groups of atoms that stay together and have a charge. l Covalently bonded l You must note these. (pg 178 Table 2)

1- ions l Acetate C 2 H 3 O 2 1- l Nitrate NO 3 1- l Nitrite NO 2 1- l Hydroxide OH 1- l Permanganate MnO 4 1- l Cyanide CN 1-

1- ions l Perchlorate ClO 4 1- l Chlorate ClO 3 1- l Chlorite ClO 2 1- l Hypochlorite 1-

2- ions l Sulfate SO 4 2- l Sulfite SO 3 2- l Carbonate CO 3 2- l Chromate CrO 4 2- l Dichromate Cr 2 O 7 2- l Silicate SiO 3 2-

3- ions l Phosphate PO 4 3- l PhosphitePO ion l Ammonium NH 4 1+

Adding Hydrogen to Polyatomics l Hydrogen ions are 1+ l Attach to other polyatomic ions- changes charge by one l Sulfate SO 4 2- l Hydrogen sulfate HSO 4 1- l Phosphate PO 4 3- l Hydrogen phosphate HPO 4 2- l Dihydrogen phosphate H 2 PO 4 1-

Ions in Ionic Compounds

Naming Binary Ionic Compounds l Binary Compounds - 2 elements. l Ionic - a cation and an anion. l The name is just the names of the ions. l Cation first anion second l Easy with Group A elements. l NaCl = Na + Cl - = sodium chloride l MgBr 2 = Mg 2+ Br - = magnesium bromide l Na 2 S

Naming Binary Ionic Compounds l The problem comes with the transition metals. l Cation name includes the charge. l The compound must be neutral. l same number of + and – charges. l Use the negative charge to find the charge on the positive ion.

Naming Binary Ionic Compounds l Write the name of CuO l Need the charge of Cu l O is 2- l copper must be 2+ l Copper(II) oxide l Name CoCl 3 l Cl is 1- and there are three of them = 3- l Co must be 3+ l Cobalt(III) chloride

Naming Binary Ionic Compounds l Write the name of Cu 2 S. l Since S is 2-, the Cu 2 must be 2+, so each one is 1+. l copper(I) sulfide l Fe 2 O 3 l Each O is 2- 3 x 2- = 6- l 2 Fe must = 6+, so each is 3+. l iron(III) oxide

Naming Binary Ionic Compounds l Write the names of the following l KCl l Na 3 N l CrN l Sc 3 P 2 l PbO l PbO 2 l Na 2 Se

Ternary Ionic Compounds l Will have polyatomic ions l At least three elements (3 capital letters) l Still just name the ions l NaNO 3 l CaSO 4 l CuSO 3

Ternary Ionic Compounds l (NH 4 ) 2 O l Fe(OH) 3 l LiCN l (NH 4 ) 2 CO 3 l NiPO 4

Writing Formulas l The charges have to add up to zero. l Get charges on pieces. l Cations from name or periodic table. l Anions from periodic table or polyatomic. l Balance the charges by adding subscripts. l Put polyatomics in parenthesis if there is more than one of them

Writing Formulas l Write the formula for calcium chloride. l Calcium is Ca 2+ l Chloride is Cl 1- l Ca 2+ Cl 1- would have a 1+ charge. l Need another Cl 1- l Ca 2+ Cl 2 1-

Crisscross l Switch the numerical value of the charges Ba 2+ N Ba 3 N2N2 l Reduce ratio if possible

Write the formulas for these l Lithium sulfide l tin (II) oxide l tin (IV) oxide l Copper (II) sulfate l Iron (III) phosphide l gallium nitrate l Iron (III) sulfide l ammonium sulfide

Write the formulas for these l Ammonium chloride l barium nitrate

Yes Charge from name Charge from table No Formula and charge from memory Charge from table YesNo M +X Nm -Y M Y Nm X Ionic Roman Numeral? Polyatomic?

Yes Metal Metal (charge) NameName +ide Ionic Yes No Group 1A, 2A or 3A? Poly atomic?

Things to look for l If cations have (), the number is their charge. Not how many. l If anions end in -ide they are probably off the periodic table (Monoatomic) l If anion ends in -ate or -ite it is polyatomic l The positive piece always gets written first l Hydrogen- it depends on where it’s at –If it is second, it’s a nonmetal -hydride

Molecular Compounds Writing names and Formulas

Molecular compounds l made of just nonmetals l smallest piece is a molecule l can’t be held together because of opposite charges. l can’t use charges to figure out how many of each atom

Easier l Ionic compounds use charges to determine how many of each. –Have to figure out charges. –Have to figure out numbers. l Molecular compounds name tells you the number of atoms. l Uses prefixes to tell you the number

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

Naming lElException - we don’t write mono- if there is only one of the first element. lNlNo ao oo double vowels when writing name, io, oi, and ai are okay. PrefixnamePrefixname-ide lTlTo write the name write two words

Name These lN2OlN2O l NO 2 l Cl 2 O 7 l CBr 4 l CO 2 l BaCl 2

Write formulas for these l diphosphorus pentoxide l tetraiodine nonoxide l sulfur hexaflouride l nitrogen trioxide l Carbon tetrahydride l phosphorus trifluoride l aluminum chloride l diagram diagram

Name 1 Name 2 No Yes No Does Name 2 have a prefix?

Nm Prefix

Yes No XxYyXxYy Is X a metal? Yes No

Prefix+namePrefix+name+ide (no mono) Molecular

Acids Writing names and Formulas

Acids l Compounds that give off hydrogen ions when dissolved in water. l Must have H in them. l will always be some H next to an anion. l The anion determines the name.

Naming acids l If the anion attached to hydrogen is ends in -ide, put the prefix hydro- and change -ide to -ic acid l HCl - hydrogen ion and chloride ion l hydrochloric acid l H 2 S hydrogen ion and sulfide ion l hydrosulfuric acid

Naming Acids l If the anion has oxygen in it l it ends in -ate or -ite l change the suffix -ate to -ic acid l HNO 3 Hydrogen and nitrate ions l Nitric acid l change the suffix -ite to -ous acid l HNO 2 Hydrogen and nitrite ions l Nitrous acid

Name these l HF lH3PlH3P l H 2 SO 4 l H 2 SO 3 l HCN l H 2 CrO 4

Writing Formulas l Hydrogen will always be first l name will tell you the anion l make the charges cancel out. l Starts with hydro- no oxygen, -ide l no hydro, -ate comes from -ic, -ite comes from -ous

Write formulas for these l hydroiodic acid l acetic acid l carbonic acid l phosphorous acid l hydrobromic acid l diagram diagram

Name 1 Name 2 No Yes Is Name 2 acid? Yes No Does Name 2 have a prefix?

No Charge from table H Y Nm Nm -Y -ate-ite No Yes NoYes Hydro- ? -ic acid?

Yes No XxYyXxYy Is X hydrogen? Is X a metal? Yes No

Hydro____ ic acid ____ ic acid____ ous acid Acid Yes No Oxygen? -ate?

38.Name these acids a) H 2 C 2 O 4 b) HFc) HClO 2 d) H 2 CO 3 39.Write formulas for these compounds a) nitrous acidb) hydroselenic acid c) phosphoric acidd) acetic acid 43. Name these compounds a) AlF 3 b) SnO 2 c) Fe(C 2 H 3 O 2 ) 3 d) KHSO 4 e) CaH 2 f) HClO 3 g) Hg 2 Br 2 h) H 2 CrO Write formulas for these a) Phosphorus pentabromide b) Carbon chloride c) potassium permanganate

43. Name these compounds a) AlF 3 b) SnO 2 c) Fe(C 2 H 3 O 2 ) 3 d) KHSO 4 e) CaH 2 f) HClO 3 g) Hg 2 Br 2 h) H 2 CrO Write formulas for these a) Phosphorus pentabromide b) Carbon chloride c) potassium permanganate d) Calcium hydrogen carbonate e) dichlorine heptoxide f) trisilicon tetrahydride g) sodium dihydrogen phosphate

Summary l Periodic table –Grouped by properties l Metals- make cations –2 types those with () and those without l Nonmetals make anions –Three types Without O -ide With O -ite and -ate l Only electrons can move to make ions

Summary l Make all the decisions. l First determine type of compound l Then figure out name or formula l Acid = H to start l Metal = Ionic l No H, No metal = molecular l Only molecular get prefixes l Roman numeral is NOT how many l Hydro means no O