Learning Stuff

Rules for Assigning Oxidation States

The oxidation state (OS) of an element corresponds to the number of electrons, e-, that an atom loses, gains, or appears to use when joining with other atoms in compounds. In determining the OS of an atom, there are seven guidelines to follow:

A Hierarchy of Rules for Assigning Oxidation Numbers

1.   
Oxidation numbers must add up to the charge on the molecule, formula unit, or ion.
2.   
The atoms of free elements have oxidation numbers of zero.
3.   
Metals in Groups 1A, 2A, and Al have +1, +2, and +3 oxidation numbers, respectively.
4.   
H and F in compounds have +1 and -1 oxidation numbers, respectively.
5.   
Oxygen has a -2 oxidation number.
6.   
Group 7A elements have a -1 oxidation number.
7.   
Group 6A elements have a -2 oxidation number.
8.   
Group 5A elements have a -3 oxidation number.
9.   
When there is a conflict between two of these rules or an ambiguity in assigning an oxidation number, apply the rule with the lower number and ignore the conflicting rule.


Specific Heats (Csp)

SubstanceFormulaPhaseCsp (J/goC)
AluminumAlsolid0.900
CadmiumCdsolid0.232
ChromiumCrsolid0.448
CopperCusolid0.385
DiamondCsolid0.519
GoldAusolid0.129
GraphiteCsolid0.711
HeliumHegas5.19
HydrogenH2gas14.3
IodineI2solid0.427
IronFesolid0.444
KryptonKrgas0.247
LeadPbsolid0.159
MagnesiumMgsolid1.017
MercuryHgliquid0.138
NeonNegas1.03
NickelNisolid0.444
NitrogenN2gas1.04
OxygenO2gas0.916
PlatinumPtsolid0.133
SiliconSisolid0.703
SilverAgsolid0.237
SulfurSsolid0.732
TinSnsolid0.213
TitaniumTisolid0.523
TungstenWsolid0.133
UraniumUsolid0.115
WaterH2Oliquid4.184
XenonXegas0.158
ZincZnsolid0.388
From: http://owl.cengage.com/departments/GenChemKotz7eDemo0709/appendix/SpecificHeats.html