Introduction
Potassium dichromate is a bright orange-red crystalline compound that is commonly used in the laboratory for various purposes. It is a powerful oxidizing agent, and it is also used as a primary standard for the calibration of analytical instruments. In this article, we will discuss how to write the chemical formula for potassium dichromate.
The Chemical Formula
The chemical formula for potassium dichromate is K2Cr2O7. This means that it consists of two potassium atoms, two chromium atoms, and seven oxygen atoms. In order to write the chemical formula for any compound, you need to know the valency of each element and how many atoms of each element are present in the compound.
Valency of Potassium
Potassium is a metal that belongs to the alkali metal group in the periodic table. It has a valency of +1, which means that it can form only one bond with other elements.
Valency of Chromium
Chromium is a transition metal that belongs to the sixth group in the periodic table. It has two valencies, +2 and +6. In potassium dichromate, chromium has a valency of +6.
The Oxygen Atoms
Oxygen is a non-metal that belongs to the sixth group in the periodic table. It has a valency of -2, which means that it can form two bonds with other elements.
How to Write the Chemical Formula
Now that we know the valency of each element, we can write the chemical formula for potassium dichromate. We start by writing the symbol of the first element, which is potassium. Since potassium has a valency of +1, we need two atoms of potassium to balance the valency of chromium. So we write K2. Next, we write the symbol of the second element, which is chromium. Since chromium has a valency of +6, we need two atoms of chromium to balance the valency of potassium. So we write Cr2. Finally, we write the symbol of the third element, which is oxygen. Since oxygen has a valency of -2, we need seven atoms of oxygen to balance the valency of potassium and chromium. So we write O7. Putting it all together, we get K2Cr2O7, which is the chemical formula for potassium dichromate.
Conclusion
Writing the chemical formula for a compound may seem daunting at first, but it is actually quite simple once you know the valency of each element. In the case of potassium dichromate, we need to balance the valencies of potassium, chromium, and oxygen to arrive at the correct formula. With this knowledge, you can confidently write the chemical formula for any compound you encounter in the laboratory.