NAMING AND WRITING FORMULAS FOR COMPOUNDS

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IUPAC BOHR DIAGRAMS FOR ATOMS TYPES OF CHEMICAL BONDS MOLECULAR COMPOUNDS

◦ TYPES SIMPLE COVALENT COMMON NAME

IONIC COMPOUNDS◦ SIMPLE IONIC◦ MULTIVALENT◦ POLYATOMIC/COMPLEX◦ HYDRATED IONIC

ACIDS2

International Union of Pure and Applied Chemists

A global organization that sets the standards in chemistry.

One job of the IUPAC is to give compounds SYSTEMIC NAMES.

AKA:ENERGY LEVEL DIAGRAMS

These are a way of drawing atoms in a 2-D manner.

Keep in mind that atoms are actually 3-D, and there are more complex representations of atoms.

Bohr models show the NUCLEUS and the ELECTRON ENERGY LEVELS of an atom.

3 types of SUBATOMIC PARTICLES ◦PROTONS (p+) Positively charged particles – large mass Atomic Number = Number of Protons

◦ELECTRONS (e-) Negatively charged particles – very small mass Number of Electrons = Number of Protons

◦NEUTRONS (no) Neutral particles – large mass Number of neutrons = Atomic Mass – Atomic Number

NUCLEUS◦ center of the atom◦ contains p+ and n0

◦ atomic mass is concentrated here

ELECTRON ENERGY LEVELS◦ areas around the nucleus where electrons may be found◦ 3 LEVELS:

FIRST LEVEL (Closest to Nucleus) maximum of 2 e- SECOND LEVEL maximum of 8e- THIRD LEVEL maximum of 8e-

EXAMPLE: DRAW BOHR DIAGRAMS FOR:

Li – lithium atom

◦ ATOMIC # = _____________◦ ATOMIC MASS = _____________◦ # p+ = ________________________◦ # e- = ________________________◦ # no = ________________________

Ne – neon atom

S – sulfur atom

Do Bohr diagrams for the first 18 elements.

Be sure to:◦ Write in the atomic number

and mass number.◦ Write the name of the atom.◦ Show p+ and n0 in the nucleus◦ Draw electrons in the energy

levels.

VALENCE LEVEL◦The outermost energy level ◦Electrons in this level are VALENCE ELECTRONS◦Atoms with FULL valence shells are STABLE,

meaning they do not normally react with other atoms.

Which Group???◦Atoms that do not have full electron energy levels

are unstable and must GAIN, LOSE, or SHARE electrons to become stable.

A chemical bond is a force of attraction between atoms.

2 TYPES of Chemical bonds1.COVALENT BONDS

◦AKA: molecular bonds◦“co” – together/sharing , “valent” – outer shell◦Occur when 2 nonmetals share at least 1 pair

of electrons◦Molecules with covalent bonds are NON-

ELECTROLYTES.ie. their solutions DO NOT CONDUCT electric

current

2. IONIC BOND◦Occur between a metal and a nonmetal◦Metals lose electrons to form CATIONS (+)◦Nonmetals gain electrons to form ANIONS (-)◦Ionic compounds are ELECTROLYTES. ie. their solutions CONDUCT electric current

Form when 2 or more NONMETALS share electrons in COVALENT BONDS.

2 TYPES:◦BINARY Molecular Compounds◦TRIVIAL NAME Molecular Compounds

Use these IUPAC prefixes:

Number Prefix

1 mono2 di3 tri4 tetra5 penta6 hexa7 hepta8 octa9 nona

10 deca18

1. Write NAMES of elements, with the 2nd element ending in “-ide”.

2. Use PREFIXES to indicate the number of each atom.

3. Do NOT use the prefix “mono” for the 1st element.DO use “mono” with the 2nd element.

N2O4 ________________________

P2O5________________________

CCl4 ________________________

S2H2 ________________________

CO ________________________

1. Write ELEMENT SYMBOLS for each element in the compound.

2. Use each PREFIX to write the number of each atom as a SUBSCRIPT next to the symbol

(omit the subscript 1).

carbon monoxide ____________

triphosphorus pentabromide ____________

sulfur hexafluoride ____________

dicarbon tetrahydride ____________

AKA: COMMON NAME molecular compounds.

These must be memorized.

FORMULA TRIVIAL/COMMON NAMEO3 ozone

H2O waterH2O2 hydrogen peroxideNH3 ammoniaCH4 methane

CH3OH methanolC2H5OH ethanolC6H12O6 glucose

C12H22O11 sucrose23

Complete the NEXT THREE SHEETS in your handout for HOMEWORK.

Refer to the following notes for help:◦FIRST SHEET

Given Name, Write Formula Notes

◦SECOND SHEET Given Formula, Write Name Notes

◦THIRD SHEET Everything! Watch out for those common name molecular

compounds!!!

Atoms that are not NOBLE GASES will GAIN, LOSE, or SHARE ELECTRONS to become more stable.

SHARING electrons results in a COVALENT BOND and a MOLECULAR COMPOUND.

When an atom loses or gains electrons it forms an ion.

A ionic bond is a force of attraction between positive and negative ions.

OCTET RULE◦Atoms that have an octet of valence

electrons are STABLE and UNREACTIVE.29

Cations+

- POSITIVE ions that are formed from a LOSS of electrons.

Cations have more PROTONS than ELECTRONS and therefore has a net POSITIVE charge.

- METALS form cations.

anionsreegative

- NEGATIVE ions that are formed from a GAIN of electrons.

Anions have more ELECTRONS than PROTONS and therefore has a net NEGATIVE charge.

- NONMETALS form anions.

Electron Blues

METALS◦ ATOMS of METALS will LOSE electrons to become CATIONS.◦ ATOMS with 1, 2, or 3 VALENCE electrons will LOSE these

electrons to form 1+, 2+, or 3+ ions respectively.

◦GROUP 1 ATOMS – ALKALI 1 valence electrons(s) (will lose 1 to become stable) 1 + ion

◦GROUP 2 ATOMS – ALKALINE EARTH 2 valence electrons(s) (will lose 2 to become stable) 2 + ion

◦GROUP 13 ATOMS 3 valence electrons(s) (will lose 3 to become stable) 3 + ion

NONMETALS◦ ATOMS of NONMETALS will GAIN electrons to become ANIONS.◦ ATOMS with 5,6, or 7 VALENCE electrons will GAIN these electrons to form 3-, 2-,

or 1- ions respectively.

◦ GROUP 15 ATOMS 5 valence electrons(s) (will gain 3 to become stable) 3 - ion

◦ GROUP 16 ATOMS 6 valence electrons(s) (will gain 2 to become stable) 2 - ion

◦ GROUP 17 ATOMS - HALOGENS 7 valence electrons(s) (will gain 1 to become stable) 1 - ion

◦ GROUP 18 ATOMS - NOBLE GASES FULL outer valence levels

Made from a METAL and a NONMETAL Metals form CATIONS Nonmetals form ANIONS An IONIC BOND is the force of attraction between cations and anions

(opposite charges attract) Ions are arranged in a CRYSTAL LATTICE.

eg. NaCl crystal lattice

eg. NaCl

Cl- Na+

Each cations is surrounded by 6 anions and vice versa

See Figure 4, p. 189

Cl- Na+ Cl- Na+ Cl- Na+

Cl-Cl- Na+ Cl- Na+ Cl- Na+Na+

Cl- Na+ Cl- Na+ Cl- Na+Cl- Na+

Cl-Cl- Na+ Cl- Na+ Cl- Na+Na+

WRITE THE NAME FROM THE FORMULA

1. Write the name of the CATION before the ANION

(Be positive before being negative

2. Change the ANION suffix to “-ide”

• two types of ion (a cation and an anion)• cations only have ONE possible charge

Do NOT use

CAPITALS

Do NOT use

PREFIXES41

MgBr2 _____________________________KCl _______________________________Na2S _____________________________

Mg3P2 _____________________________

Ba3N2 ______________________________ What’s wrong with these for BaS?barium sulfur Barium Sulfide barium sulfuride

Do the following sheet in the booklet for homework:

Follow rules for:◦“GIVEN FORMULA, WRITE NAME” for Ionic

Compounds.

WRITE THE FORMULA FROM THE NAME1. Determine each ION CHARGE from the periodic

table.2. Use the “crossover” method to write the formula for

the compound.

The overall charge on a compound is “zero”. Ion ratios must be reduced to lowest terms.

EXAMPLE: sodium bromide _____________________

barium iodide ___________________

EXAMPLE: magnesium oxide _____________________

aluminum oxide ___________________

Do the next two sheets for homework!

FIRST PAGE:◦Given NAME, Write

FORMULA

SECOND PAGE:◦TOP HALF – Molecular

Compound Naming◦BOTTOM HALF – Ionic

Compound Naming

1. ROMAN NUMERALS show the ION CHARGE of the MULTIVALENT ION.

2. If a ROMAN NUMERAL is NOT given, use the charge found on the top in each box on the table. (most common charge)

EXAMPLE: copper (II) oxide

_________________________

lead (IV) sulfide_________________________

tin sulfide_________________________

Do the sheet on the following page!

Remember to ONLY use the ROMAN NUMERAL with the MULTIVALENT IONS!!!

RULES1. Write the names of the ions.

2. Write the ROMAN NUMERAL for the MULTIVALENT ION. There are 2 METHODS:

1. METHOD 1 Charges must add up to zero.

1. METHOD 2 Charge of Anion X Subscript of AnionSubscript of Cation

PbI2 _________________________

Fe2O3 _________________________

CuCl _________________________

MnO2 _________________________

Do the next 2 sheets for homework!

Remember, doing some workings can help prevent any mistakes!!!

lithium sulfate _____________________

ammonium carbonate_____________________

hydrogen dichromate _____________________

sodium acetate _____________________

lead (II) nitrate _____________________

calcium hydroxide _____________________

HNO3 _____________________

NaOH _____________________

KMnO4_____________________

Cu2SO4_____________________

hydrogen carbonate is AKA bicarbonate HCO3-

hydrogen sulfate is AKA bisulfate HSO4-

tetraborate B4O72-

silicate SiO32-

glutamate C5NH8O4-

Do the next 2 Sheets for homework!!!

Remember to use the crossover method for charges.

You may find it helpful to use BRACKETS around ALL polyatomic ions when writing the formulae.

1. Simple Ions

Names Formulas- write the name of the positive ion - determine the charge on each ion

- write the name of the negative ion - cross over the charges to write the formula followed by -ide

eg. NaCl sodium chloride eg. calcium phosphide

Mg3N2 magnesium nitride Ca2+ P3-

2. Polyatomic Ions

- write the name of the negative ion - cross over the charges to write the formula

eg. CaSO4 calcium sulfate eg. magnesium nitrate

Al(OH)3 aluminum hydroxide Mg2+ NO3-

Mg(NO3)2

3. MultiValent Metals- use Roman Numerals to indicate the ion charge(Stock System)

- use the suffix -ic to indicate the smaller ion charge or -ous for the larger ion charge.

Names Formulaseg. CoCl2 - cobalt(II) chloride eg. nickel(II) nitride

- cobaltous chloride Ni2+ N3- (cross over)CoCl3 - cobalt(III) chloride

- cobaltic chloride Ni3N2

NOTE: After crossing over the charges to get the formula, make sure you are using thesimplest ratio between the ions.eg. magnesium oxide - Mg2O2 becomes MgO

DON’T USE PREFIXES FOR IONIC COMPOUNDS.

1. Simple Ions

- write the name of the negative ion - cross over the charges to write the formula followed by -ide

eg. NaCl sodium chloride eg. calcium phosphide

Mg3N2 magnesium nitride Ca2+ P3-

2. Polyatomic Ions

- write the name of the negative ion - cross over the charges to write the formula

eg. CaSO4 calcium sulfate eg. magnesium nitrate

Al(OH)3 aluminum hydroxide Mg2+ NO3-

Mg(NO3)2

3. MultiValent Metals- use Roman Numerals to indicate the ion charge(Stock System)

- use the suffix -ic to indicate the smaller ion charge or -ous for the larger ion charge.

Names Formulaseg. CoCl2 - cobalt(II) chloride eg. nickel(II) nitride

- cobaltous chloride Ni2+ N3- (cross over)CoCl3 - cobalt(III) chloride

- cobaltic chloride Ni3N2

NOTE: After crossing over the charges to get the formula, make sure you are using thesimplest ratio between the ions.eg. magnesium oxide - Mg2O2 becomes MgO

DON’T USE PREFIXES FOR IONIC COMPOUNDS.

Hydrated ionic compounds have WATER attached to their crystal lattice structure.

Solutions become hydrated when they are crystallized from a water solution.

They are often recognizable by eye because they are often SHINY and TRANSLUCENT.

Examples: ◦ Bluestone, Epsom salts, Rock salts

BLUESTONE CuSO4 ∙5H2O◦ 5 CuSO4 molecules attached to each

H2Ocompound.◦ The “dot” represents a weak bond.

We indicate the presence of water with the word HYDRATE and we indicate the number of water molecules with our GREEK PREFIXES:

MONO 1, DI 2, TRI 3, TETRA 4, PENTA 5, HEXA 6, HEPTA 7, OCTA 8, NONA 9, DECA 10

ANHYDROUS: NO water attached

barium chloride dihydrate _____________________

potassium hydroxide hexahydrate _____________________

sodium carbonate octahydrate _____________________

cobalt (II) chloride decahydrate _____________________

CaSO4 ∙2H2O _____________________

Na3PO4 ∙4H2O ______________________

HCN ∙ 3H2O _____________________

HOMEWORK:◦ DO THE SHEET ON HYDRATED IONIC COMPOUNDS

ON THE NEXT PAGE OF YOUR HANDOUT.

NAMING AND WRITING FORMULAS FOR COMPOUNDS

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