- Criss Cross Method PDF

Title	- Criss Cross Method
Course	Physical Chemistry I
Institution	The City College of New York
Pages	2
File Size	68.9 KB
File Type	PDF
Total Downloads	90
Total Views	154

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Summary

Download - Criss Cross Method PDF

Description

The criss-cross method of balancing charge! Ionic compound formulas must contain the fewest number of ions that “balance” out positive and negative charge (the same amount of each). The “criss-cross” method is one way of writing the formulas properly. The formula for ionic compounds is called a “formula unit.” 1. Write symbols and charges of ions.

Cu2+ , P3-

2. Crisscross: Cu2+ 3 , P3 -2 The cation charge becomes the anion subscript The anion charge becomes the cation subscript 3. Clean up format for final answer - do NOT write ionic charges - reduce subscripts to lowest ratio - do NOT write the subscript “1”

Cu3P2

Use the criss-cross method to write formula units for these ionic compounds (2 examples are done for you)

Na+

ClNaCl

O2Na2O

P3-

S2-

Na3P

Na2S

K+

KCL

K 2O

K3P

K 2S

Ba2+

BaCl2

BaO

Ba3P2

BaS

Fe2+

FeCl2

FeO

Fe3P2

FeS

Cr3+

CrCl3

Cr2O3

CrP

Cr2S3

Li+

LiCl

Li2O

Li3P

Li2S

Mg2+

MgCl2

MgO

Mg3P2

MgS

Al3+

AlCl3

Al2O3

AlP

Al2S3

Ga3+

GaCl3

Ga2O3

GaP

Ga2S3

Sn2+

SnCl2

SnO

Sn3P2

SnS

Ca2+

CaCl2

CaO

Ca3P2

CaS...