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Regents Chemistry: Mr. Palermo

Notes: Unit 2: Naming

and Formula Writing

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UNIT 2: NOMENCLATURE &

FORMULA WRITING WWW.MRPALERMO.COM

LESSON 1: NAMING & FORMULA WRITING (BINARY COMPOUNDS)

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OBJECTIVE: BY THE END OF THIS VIDEO

YOU WILL BE ABLE TO:

ü  Identify the various parts of a chemical formula

ü  Identify binary compounds by name ü Construct chemical formulas for

binary compounds

RECALL

•  Coefficient: in front of Formula •  Subscript: small # after an atom •  Subscript after ( ) multiply everything

inside by that # Example: 2Ca(NO3)2

# of atoms of each substance in the formula above: 2Ca, 4N, 12O

EXAMPLE:

How many atoms of each substance are in the formula 3Na2SO4 ?

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CHECK YOUR UNDERSTANDING

ü Can you identify the various parts of a chemical formula

RECALL

•  Elements cannot be broken down by physical or chemical changes.

•  Compounds are composed of 2 or more elements that can be broken down by chemical change.

•  What type of matter can be broken down by physical changes?

IONS

•  Ions are elements with a charge. The reference table lists these charges for each element.

•  If the element is positive, it is called a cation. •  Cations are named the same as the element.

(Example: Ca=Calcium atom / Ca+2=Calcium ion)

•  If the element in negative, it is called an anion. •  Anions are named ending with “-ide”

(Example: N=Nitrogen atom / N-3 = Nitride ion)

EXAMPLE:

•  Mg+2 •  K+ •  O-2 •  F- •  Li+ •  I-

BINARY COMPOUNDS

•  Binary Compounds consist of only two of elements.

Example: NaCl

NAMING BINARY COMPOUNDS

•  Write the complete name of the first element.

•  The second element should then be named using the first syllable with the ending

“-ide.” •  NaCl sodium chloride •  KI potassium iodide •  MgCl2 magnesium chloride •  Ca3N2 calcium nitride

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EXAMPLE

•  Li3P •  Al2S3 •  SrBr2 •  Rb2O •  BaSe •  CsI

CHECK YOUR UNDERSTANDING

ü Can you identify binary compounds by name

WRITING CHEMICAL FORMULAS

•  Sum of charges (oxidation numbers) in a compound equal zero

•  Ex. Na+1Cl-1 (+1) + (-1) = 0

WRITING FORMULAS

1. Write each ion separately with their charges

2. CRISS CROSS & REDUCE the charges not the signs

3. Write numbers as subscripts 4. Do not write 1’s

EXAMPLE:

•  Compound containing Magnesium and Chlorine

Mg+2 Cl-1 MgCl2

EXAMPLE:

•  Compound containing Barium and Oxygen

Ba+2 O-2 BaO

Ba2O2

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EXAMPLE:

Calcium and Fluorine CaF2

CHECK YOUR UNDERSTANDING

ü Can you construct chemical formulas for binary compounds

YOU SHOULD BE ABLE TO:

ü  Identify the various parts of a chemical formula

ü  Identify binary compounds by name ü Construct chemical formulas for

binary compounds

LESSON 2: NAMING & FORMULA WRITING (MULTIPLE CHARGES)

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OBJECTIVE: BY THE END OF THIS VIDEO

YOU WILL BE ABLE TO:

ü  Identify binary compounds containing multiple charges by name using roman numerals

ü Construct chemical formulas for binary compounds containing multiple charges

PROBLEM:

•  FeCl2 and FeCl3 are different compounds but seem to have the same name. How can we name them different?

•  FeCl2 is iron (II) chloride FeCl3 is iron (III) chloride.

•  What do the roman numerals represent?

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TRANSITION METALS AND NONMETALS

 Transition Metals are in the middle group of the periodic table.

 Nonmetals are on the right side of the staircase.

TRANSITION METALS AND NONMETALS

 They can have multiple charges or oxidation numbers and so you must show which charge you are using with roman numerals:

Example: Iron (II) oxide

HOW TO DETERMINE THE CHARGE?

1.  Find the charge of the anion (the element listed last in the formula) It will always be negative charge

2.  Set the whole thing equal to zero (since compounds are always neutral)

3.  Then solve for the the charge of the cation

Example: FeCl3

NAMING BINARY COMPOUNDS CONTAINING MULTIPLE CHARGES

4.  Now name the compound as you did in lesson 1 except you indicate the charge of the cation (first element) with roman numerals

EXAMPLE

•  FeCl2

•  CuF

•  Ni2O3

EXAMPLE

•  N2O3

•  SO4

•  PCl3

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CHECK YOUR UNDERSTANDING

ü Can you identify binary compounds containing multiple charges by name using roman numerals

WRITING CHEMICAL FORMULAS

Example: cobalt (II) chloride chromium (III) oxide nitrogen (II) fluoride

CHECK YOUR UNDERSTANDING

ü Can you construct chemical formulas for binary compounds containing multiple charges

YOU SHOULD BE ABLE TO:

ü  Identify binary compounds containing multiple charges by name

ü Construct chemical formulas for binary compounds containing multiple charges

LESSON 3: NAMING & FORMULA WRITING (TERTIARY COMPOUNDS)

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OBJECTIVE: BY THE END OF THIS VIDEO

YOU WILL BE ABLE TO:

ü  Identify tertiary compounds containing polyatomic ions by name

ü Construct chemical formulas for tertiary compounds containing polyatomic ions

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TERTIARY COMPOUNDS

•  When compounds have more than 2 elements, it contains a polyatomic ion (TABLE E).

•  Polyatomic ion are a group of 2 or more atoms that are bonded very strongly and act as one ion. They bond with other ions to for compounds.

Example: NO3-1

NAMING TERTIARY COMPOUNDS

•  Follow same rules as naming binary compounds except:

•  The polyatomic ions on TABLE E are named according to the table

Example: NaNO3 Sodium Nitrate

EXAMPLE

•  CaCO3 calcium carbonate •  LiClO2 lithium chlorite •  NaOH sodium hydroxide •  (NH4)3PO4 ammonium phosphate

CHECK YOUR UNDERSTANDING

ü  Identify tertiary compounds containing poly atomic ions by name

WRITING FORMULAS CONTAINING POLYATOMIC IONS

•  Same as Binary Compounds -  Never change the polyatomic ion

subscripts -  If more than 1 polyatomic ion put in

parenthesis followed by subscript

EXAMPLE

•  Write the formula for ammonium chloride

NH4+1 Cl-1 NH4Cl

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EXAMPLE:

•  Write the formula for Lithium Carbonate

Li+1 CO3-2 Li2CO3

EXAMPLE:

•  Write the formula for Calcium Hydroxide

Ca+2 OH-1 Ca(OH)2

CHECK YOUR UNDERSTANDING

ü Construct chemical formulas for tertiary compounds containing polyatomic ions

YOU SHOULD BE ABLE TO:

ü  Identify tertiary compounds containing polyatomic ions by name

ü Construct chemical formulas for tertiary compounds containing polyatomic ions