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Chemical Nomenclature

How to write and say chemical formulas

Elements

� Elements are said with just their name

� Mg = magnesium

� Ca = calcium

Compounds

� Most elements are not found separately

but combined in a compound with something else

� The reason for this is the octet rule

We want 8…eight is great!

Octet Rule

� Noble gases are what all elements aspire to

be like electronically

� These elements have

8 electrons in highest energy level

Ionic Bond

� Atoms will either give up or take electrons

to get to have eight in their highest energy level

Hey, can you

help me out

and gimme an electron?

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Why certainly, I have one I don’t

want anyway.

Give up/take away electrons

Charges

� Sodium now has a +1 charge since it has

lost an electron

� Chlorine a minus charge since it gained an

electron

Ionic Bond

� Opposites attract, so a bond is formed

between the two of them.

(or until water

breaks us apart)

“Perhaps one of you gentlemen would mind telling me justwhat is outside the window that you find so attractive..?”

Image courtesy NearingZero.net

“Perhaps one of you gentlemen would mind telling me justwhat is outside the window that you find so attractive..?” Ionic Compound

� The combination of Na+ and Cl- form the

compound NaCl

� An ionic compound will always consist of:

� A metal ion (also called a cation, the + one)

� A non-metal ion (also called an anion, the - one)

� CATION ALWAYS COMES BEFORE THE ANION; both in the name and the formula

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Naming Ionic Compounds

� When naming ionic compounds

� Just say the name of the metal

� For the non-metal, drop the ending and add -ide to it.

� NaCl = sodium chloride

Practice Problem #1

� Name the following ionic compounds

1. ZnO

2. LiBr

3. Mg3N2

4. BaS

5. K3P

Zinc oxide

Lithium bromide

Magnesium nitride

Barium sulfide

Potassium phosphide

Determining metal and non-metal charge

� Where are the metals on the periodic

table?

� Metals always have what charge?

� Where are the nonmetals?

� Nonmetals always have what charge?

We’ll see the charges of the different families on

the following slide.

Using the periodic Table to find an ion’s charge

We’re going to

forget all about

the middle of

the table for

now.

+1

+2

-1

-2

-3

-4

Writing Ionic Formulas

� When combining a metal and a non-metal, the overall charge of the compound must be zero.

You must balance out the overall

charge!

Combining metals and nonmetals

� Take for instance calcium nitride.

� What is the charge of the calcium ion?

� What is the charge of the nitride ion?

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Combining metals and nonmetals

� Ca+2 means each calcium ion has 2 more

electrons than it wants

� N-3 means each nitride ion needs 3 more

electrons.

Hey buddy, can you spare 3

electrons?

Sorry, I only have two.

Maybe I can help!

YEAH!YEAH!

HEY, What

about me?

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Hang loose, man.

I’ll get one of my buddies.

YO, YO, YO. Your hero has

arrived.

YEAH!

I still need two more.

I need to get rid of two more.

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The ions found they were still attracted to one another due to their opposing charges. And they all

lived happily ever after.

Practice Problem #2

� Give the formulas for the following

compounds

1. Beryllium iodide

2. Potassium sulfide

3. Magnesium oxide

4. Strontium fluoride

BeI2

K2S

MgO

SrF2

Now is the time to learn “SWITCHY SWITCHY”

and reduce!

Transition Metals

� The middle block of elements

� All cations

� Most can take on

multiple charges

� Some Exceptions

� Zn = +2

� Ag = +1

Transition metal compounds

� In order to tell what charge a transition

metal has, put its charge in parenthesis in the name only

� For instance Copper (II) Oxide means…

� the copper ion here has a +2 charge

� For instance Copper (I) Oxide means…

� the copper ion here has a +1 chargeWhat are the formulas of these two ionic compounds?

Practice Problem #3

� Give the formula of the following

compounds:

1. Tungsten (IV) Chloride

2. Gold (III) phosphide

3. Tin (II) fluoride

4. Zinc sulfide

WCl4

AuP

SnF2

ZnS

Polyatomic Ions

� Sometimes, atoms get together but can’t quite get to an overall zero

charge.

� This is where they become a

polyatomic ion

� They’re still a charged particle (mostly anions) so they can combine

with an opposing charged ion to produce a compound

� Naming is easy, we just say the name of the polyatomic ion

With polyatomic ions we don’t have to

change the ending

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Ionic Compounds involving a polyatomic ion

Ionic Compounds involving a polyatomic ion

Ionic Compounds involving a polyatomic ion

Practice Problem #4

� Name the following compounds

1. (NH4)2S

2. CaSO4

3. Ba(NO3)2

4. K2CO3

5. Mg3(PO4)2

Ammonium sulfide

Calcium sulfate

Barium nitrate

Potassium carbonate

Magnesium phosphate

Practice Problem #5

� Write formulas for the following

compounds

� Aluminum nitrate

� Beryllium sulfate

� Calcium phosphite

� Ammonium sulfite

� Strontium nitrite

Al(NO3)3

BeSO4

Ca3(PO3)2

(NH4)2SO3

Sr(NO2)2

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Covalent Bonds

� Compounds formed by two non-metals

� More of a sharing of electrons rather than

a give-take relationship

Can you

spare an

electron?

JINX!

Why don’t you share an electron? You know

sharing is caring!

Co=together

Valent=valence electrons…

therefore, covalent is sharing electrons!

Naming Covalent Bonds

� Prefixes on back of periodic table

� If there is only one of the first element, no

prefix. Otherwise attach prefix

� Second always gets prefix and -ide ending

(just like ionic anion)

� Name these

� NO2

� N2O

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The Diatomic Molecules

� These would still be said by their elemental name but would be written with a subscript of 2

� N2

� O2

� F2

� Cl2� Br2

� I2� H2

Practice Problem #7

� Name the following covalent compounds

1. CO2

2. PCl5

3. CO

4. P3F

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Carbon dioxide

Phosphorous pentachloride

Carbon monoxide

Triphosphorous hexaflouride

Practice Problem #8

� Give the formula for the following

compounds

� Sodium acetate

� Nickel (II) chloride

� Carbon dioxide

� Sulfur trioxide

� Triphosphorous tetrachloride

NaC2H3O2

NiCl2

CO2

SO3

P3Cl4

One more thing…

� If the ionic compound begins with a hydrogen ion, it’s an acid

� We name binary acids by adding hydro as a prefix to the root of the anion and add ic, then add the word acid

� Name these:� HCl

� HI

� HF

� HBr

Acids involving polyatomic anions

� These are even easier,

� They’ll always involve oxygen

� If an -ate ion, use root of polyatomic and add -ic

� If an -ite ion, use root of polyatomic and add -ous

� Then just add the word acid

If I ATE it I would say IC!

Practice Problem #6

� Write the formulas for these acids

1. Sulfuric acid

2. Sulfurous acid

3. Carbonic acid

4. Nitric acid

5. Nitrous acid

6. Phosphoric acid

7. Phosphorous acid

H2SO4

H2SO3

H2CO3

HNO3

HNO2

H3PO4

H3PO3

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