Loading....
Coupon Accepted Successfully!

 

Guidelines for Writing Chemical Formulas

Step 1: Write the symbols of the two radicals––the positive radical to the left and the negative radical to the right.

Step 2: The symbols or formulae of radicals are written. The valency of each element/radical is indicated at the top.
 
Example: Calcium chloride
 
 

Step 3: Applying the inter-valence rule, cross-multiply the valency of each atom or radical. Place the number at the lower right side of each radical as a subscript. In case of a compound radical, enclose it within brackets and place the number outside the brackets.
 
Examples of some common cations and anions with different charges are given in Tables 5.3 and 5.4, respectively.

 

Table 5.3 Some Common Cations (Basic Radicals)

 

+1 Charge

+2 Charge

+3 Charge

+4 Charge

+5 Charge

H+–hydrogen

Ca2+–calcium

Al3+–aluminium

Pt4+–platinum (IV)

Sb5+–antimony (V)

Li+–lithium

Mn2+–manganese (II)

Fe3+–iron (III)

Sn4+–tin (IV)

As5+–arsenic (V)

K+–potassium

Ba2+–barium

Sb3+–antimony (III)

Mn4+–manganese (IV)

 

Na+–sodium

Cu2+–copper (II)

Bi3+ bismuth

Pd4+–palladium (IV)

 

Ag+–silver

Fe2+–iron (II)

Cr3+–chromium (III)

Pb4+–lead (IV)

 

Cu+–copper (I)

Mg2+–magnesium

Co3+–cobalt (III)

 

 

NH +4–ammonium

Zn2+–zinc

As3+–arsenic (III)

 

 

Rb+–rubidium

Cd2+–cadmium

 

 

 

Cs+–cesium

Sn2+–tin (II)

 

 

 

Au+–gold (I)

Hg2+–mercury (II)

 

 

 

 

Ni2+–nickel

 

 

 

 

Pb2+–lead (II)

 

 

 

 

Be2+–beryllium

 

 

 

 

Co2+–cobalt (II)

 

 

 

 

Cr2+–chromium (II)

 

 

 

 

Pt2+–platinum

 

 

 

 

Sr2+–strontium

 

 

 

 

Table 5.4 Some Common Anions (Acid Radicals)

 

–1 Charge

–2 Charge

–3 Charge

–4 Charge

F –fluoride

O2 –oxide

PO 3–4–phosphate

C 4–4–carbide

Cl –chloride

S2 –sulphide

PO 3–3–phosphite

 

Br –bromide

CO 2–3–carbonate

BO 3–3–borate

 

I –iodide

SO 2–3–sulphite

P3––phosphide

 

OH –hydroxide

SO 2–4–sulphate

N3––nitride

 

CN –cyanide

HPO 2–4–hydrogen phosphate

 

 

HCO 3–bicarbonate or hydrogen carbonate

CrO 2–4–chromate

 

 

NO 2–nitrite

Cr2O 2–7–dichromate

 

 

NO 3–nitrate

C2O 2–4 –oxalate

 

 

CH3 CO2–acetate

 

 

 

H2PO4–dihydrogen phosphate

 

 

 

HSO4–hydrogen sulphate

 

 

 

ClO–hypochlorite

 

 

 

ClO 3–chlorate

 

 

 

ClO 4–perchlorate

 

 

 

MnO 4–permanganate

 

 

 

 

The ____-ate anions contain one more oxygen atom than the ______-ite anions and two more oxygen atoms than the hypo-____-ite anions. The per-____-ate anions contain one more oxygen atoms than the ____-ate anions.

 

 

Note that the charge or valence can usually be predicted for the elements in columns 1, 2, 13, 14, 15, 16 and 17 of the periodic table because those elements will gain or lose the smallest number of electrons to obtain inert gas shells.




Test Your Skills Now!
Take a Quiz now
Reviewer Name