List of Standard States of Elements and Ions

PDF LINK: Standard_States_of_Elements_&_Key_Ions

The standard States of Elements

The standard states of elements are the forms that they adopt at a temperature of 25°C and pressure of 1 atmosphere (1 atm).
These forms of the elements are the reactants in the formation equations of multi-element substances.

The heat of formation (∆H°f) of an element in its standard state is zero.

Below is the list of the elements whose standard states you need to know for this course. Please note that some elements have multiple possible forms at the standard state such as carbon, which can be either graphite or diamond. However only one of these forms is the true standard state; in those cases the proper state will be listed next to the formula for the element.


• Hydrogen            H2(g)
• Nitrogen              N2(g)
• Oxygen                O2(g)
• Fluorine               F2(g)
• Chlorine               Cl2(g)


• Bromine               Br(l)
• Mercury               Hg(l)


There are two distinct classes of elemental solids. Molecular solids, unlike other elemental solids, have specific molecular structures (arrangements of bonded atoms) that are packed close to each other (held by van der Waals forces) to form the solid. The atoms of a molecular solid are only bonded to the other atoms in their specific molecule, unlike the elements in the other elemental solids, which are bound to all their nearest neighboring elements.

Molecular Solids

Phosphorus          P4 – white

Sulfur                   S8(s) – rhombic crystalI2(s)

Iodine                   I2(s)

Solids (Non-Metal)

Silicon                  Si(s)

Carbon                 C(s) – graphite

Solids (Metal)

Lithium                Li(s)

Magnesium          Mg(s)

Sodium                Na(s)

Calcium               Ca(s)

Potassium             K(s)

Aluminum            Al(s)

Iron                      Fe(s)

Nickel                  Ni(s)

Copper                Cu(s)

Zinc                     Zn(s)

Silver                   Ag(s)

Gold                    Au(s)

Common Ionic Species in Aqueous Solution

Below is the list of common aqueous ions that you are expected to know for this course. You need to know the name, formula, and charge of each ion as the names and formulas will be used interchangeably in homework and exam questions.

Cations (positively charged ions)

Lithium ion

Sodium ion

Potassium ion

Silver ion

Copper(I) ion

Hydronium ion

Ammonium ion

Zinc ion

Cadmium ion

Magnesium ion

Calcium ion

Barium ion

Mercury (I) ion

Mercury(II) ion

Nickel(II) ion

Copper(II) ion

Lead(II) ion

Aluminum ion

Chromium(II) ion

Chromium(III) ion

Iron(II) ion

Iron(III) ion

Cobalt(II) ion

Cobalt(III) ion

Tin(II) ion

Tin(IV) ion

Manganese ion

Manganese(IV) ion

Anions (negatively charged ions)

Fluoride ion
Bromide ion
Iodide ion
Chloride ion
Hydrogen sulfate
Hydrogen phosphate 
Dihydrogen phosphate
Hydrogen carbonate



Welcome to Chem 200 & 202 Fall 2019 Semester!!!

Exam 2 will be on October 19, 2019 at 2:00 – 4:00 pm.


Here is the form for Makeup Exam Two: Makeup Exam Two. This form is for those who have already submitted their documentation to take a makeup for Exam One and have been Pre-Approved. Please make sure you fill out the form by October 18th at 5 pm. This form will allow me to contact you regarding where you will be taking your exam and to add you to the official roster.

If an emergency occurs, please fill out the form, if you will not be able to make Exam Two during the scheduled time. 

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