writing formulas!

Writing Formulas!

All compounds and molecules are neutral.

Ions have charges.

Bonding - a chemical attachment that forms a new substance.

This new substance has new chemical and physical properties

Example: Sodium is an explosive metal.Chlorine is a toxic gas.Sodium chloride is salt.

Metals Tend to lose e- Conductors Malleable and ductile

Nonmetals Tend to gain e- Non-conductors Brittle

+1+2 -1-2-3Most common charges

+3

variable charges(always positive)

+2+1

±4 0

Remember…

Opposites attract

I. Bonds

Ionic Bond- an exchange of electrons between a metal and a nonmetal.

This creates oppositely charge ions that are attracted to each other.

-Losing e- forms a Losing e- forms a cation (+ ion)cation (+ ion)

-Cats have paws-Cations are pawsitive

-Gaining e- forms an Gaining e- forms an anion (- ion)anion (- ion) -Onions make you cryOnions make you cry-Anions are negativeAnions are negative

I. BondsB. Covalent Bonds

- Formed by sharing electrons- Between two nonmetal atoms

C. C. MetallicMetallic Bonds Bonds- Formed by a - Formed by a sea of electronssea of electrons passing over the metal atoms passing over the metal atoms- flexible connection, does not - flexible connection, does not

form a fixed moleculeform a fixed molecule

II. CompoundsA. Ionic Compounds - They only have two

elements - the total amount of

positive charge must equal the total amount of negative charge

Compounds MUST be neutral

II. CompoundsA. Ionic Compounds

- subscripts are used to show how many of each element is needed to balance the overall charge

II. CompoundsA. Ionic Compounds

- the metal's name does not change

- the nonmetal retains the root of its name and adds the suffix -ide

Sodium and Chlorine

11+ 17+

11+ and 10- = 1+

Na+

17+ and 18- = 1-

Cl-

+-

NaCl sodium chloride

Magnesium and Oxygen

12+ 8+

12+ and 10- = 2+

Mg2+

8+ and 10- = 2-

O2-

2+ 2-

MgO magnesium oxide

Magnesium and Chlorine

17+ and 18- = 1-

Cl-17+ and 18- = 1-

Cl-12+ and 10- = 2+

Mg2+

17+ 12+ 17+

- -2+

MgCl2 magnesium chloride

Ionic NomenclatureWhat is the formula for

Na +1 and Cl -1

NaCl

sodium chlorideWhat are the symbols and charges?

How many of each atom is needed to make the compound neutral?


Na +1 and O -2

Na2O

sodium oxideWhat are the symbols and charges?



Al +3 and Cl -1

AlCl3

aluminum chlorideWhat are the symbols and charges?



Al +3 and O -2

Al2O3

aluminum oxideWhat are the symbols and charges?


II. Compounds

- the formula of an ionic compound must be in the lowest whole number ratio of the two elements to form a neutral compound (empirical formula)

A. Ionic Compounds


Mg +2 and O -2

MgO

magnesium oxideWhat are the symbols and charges?


II. Compounds

- metals with variable charges must include the charge in the name using Roman numerals

A. Ionic Compounds


Pb +2 and O -2

PbO

lead (II) oxideWhat are the symbols and charges?



Mn +4 and O -2

MnO2

manganese (IV) oxideWhat are the symbols and charges?



Cu +2 and N -3

Cu3N2

copper (II) nitrideWhat are the symbols and charges?


II. Compounds

Polyatomic ions- a group of covalently bonded atoms with an overall charge that react as a group

A. Ionic Compounds2. Polyatomic ion Compounds


Cu+2 and SO4 -2

Cu SO4

copper (II) sulfateWhat are the symbols and charges?



Na+1 and SO4 -2

Na2 SO4

sodium sulfateWhat are the symbols and charges?


II. Compounds

If more than one polyatomic ion is needed to make a neutral compound, you must use parenthesis to group the ion.

A. Ionic Compounds2. Polyatomic ion Compounds


Ba+2 and OH -1

Ba(OH)2

barium hydroxideWhat are the symbols and charges?



Al+3 and SO4 -2

Al2 (SO4)3

aluminum sulfateWhat are the symbols and charges?


Nonmetals

Tend to gain e- Nonconductor Brittle

II. Compounds

Nonmetals want to gain electrons. When two nonmetals are together, they share the electrons.

B. Covalent (Molecular) Compounds

Hydrogen and Hydrogen

H

H2

H

Nitrogen and Hydrogen (Ammonia)

H

H

HN

NH3

Hydrogen and OxygenH2O

H H

O

II. CompoundsNaming covalent compounds- Because covalent compounds may

form different compounds between two nonmetals with different ratios, the subscripts are denoted in the name by a prefix.

Covalent Nomenclature1 mono2 di3 tri4 tetra5 pent

6 hex7 hept8 oct9 non10 dec

II. CompoundsNaming covalent compounds- The element on the left will go first in the

name.- The element on the right will go last

in the name. The root remains the same, but the suffix –ide is added.

- The prefix in front of each element give the number of atoms (subscript written behind.)

Covalent NomenclatureWhat is the formula for

1 carbon 1 oxide

CO

carbon monoxide


1 carbon 2 oxide

CO2

carbon dioxide


2 phosphorus 5 oxide

P2O5

diphosphorus pentoxide

Is it covalent or ionic?Covalent- Look for prefixes (except dichromate)

- 2 nonmetals

- prefixes become subscripts

- Remember these are the easy ones. No charges! No crisscross!

Ionic- metal & nonmetal or metal & polyatomic

- write the symbol and charge

- balance charges to form a neutral compound (crisscross)

- check to make sure you have the lowest whole number ratio!

Write the formulas for these

lithium permanganate tetraiodide monoxide tin (II) oxide tin (IV) oxide diphosphorus pentoxide aluminum dichromate tetrasulfur hexaphosphide

Write the names of the following: KCl Cl2O7 CuSO3

CO2 CrN NaNO3

Sb2S3


nitrogen trioxide magnesium cyanide copper (II) hydroxide carbon tetrafluoride iron (III) bicarbonate manganese (IV) chlorite iron (III) carbonate

Write the names of the following: BaCl2 CaSO4

(NH4)2O LiCN Fe(OH)3 Na3N NiPO4

Write the names of the following: N2O NO2 PbO PbO2

Na2S CBr4 (NH4)2CO3

II. Compounds

The anion changes its suffix:-ate converts to -ic acid-ite converts to -ous acid-ide converts to hydro--ic acid

C. Acids - (Special Ionic Compounds)3. Acids- ionic compounds that start with H+1 plus an anion

II. Compounds

You –ate something and it made you s–ick,

and you mite give it to -ous.

C. Acids - (Special Ionic Compounds) 3. Acids- ionic compounds that start with H+1 plus an anion

Acidic NomenclatureWhat is the formula for

H+1 and Cl -1

HCl

hydrochloric acidWhat are the symbols and charges?



H+1 and SO3 -2

H2SO3

sulfurous acidWhat are the symbols and charges?



H+1 and SO4 -2

H2SO4

sulfuric acidWhat are the symbols and charges?



H+1 and CrO4 -2

H2CrO4

chromic acidWhat are the symbols and charges?


Write the names of the following:HBr H2SO4

H3PO4

HNO2

HC2H3O2 H2CO3


chloric acidsulfurous acidchromic acidhydrophosphoric acidcarbonic acidhydroiodic acid

writing formulas!

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