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How to Write Chemical Formulas: Writing Guide For Students

How to Write Chemical Formulas Properly

A chemical formula highlights each constituent element using its chemical symbol and denotes the precise number of atoms on every element. It is like presenting different ingredients that make up an item, such as pizza or bread. In formula writing in chemistry, compounds are made of several elements, and these elements are made of atoms.

Chemical formulas contain arrows, with a one-way arrow indicating the reaction of an element(s) towards another element. However, an arrow with two sides indicates that the reaction can take place either forward or backward. Here is a closer look at how to write chemical formulas correctly.

What is an Atom?

To understand how to write chemical formulas well, it is important to start by understanding atoms. These are the smallest or single units used as building blocks of an element. Indeed, everything we know of in the world today, such as human body and rocks, is made of atoms.

Matter that contains only one type of atom is referred to as an element. However, if it contains atoms of different types, it is referred to as a molecule. It is also important to point out that atoms can form molecules with complex shapes. For example, carbon atoms can link to create spherical molecules of interconnected pentagons and hexagons.

A Brief Look into Chemical Formulas

A chemical formula is a symbolic method of presenting elements and the number of atoms. The symbol represents the type of element or atom. According to the rules for writing chemical formulas, the atoms and elements are represented using subscript numbers.

If you take the example of H2O, it implies that the water molecule comprises two hydrogen atoms and one oxygen atom.

how to write chemical formulas

How Do You Write a Chemical Formula?

Understanding how to how to write chemical formulas for molecules and atoms correctly comes with a number of benefits, including:

  • Chemical formulas are important, especially for chemists, trainers, industrialists and doctors, because they are required to write them many times. If they were to do it in full, it would require a lot of time to write and read.
  • Writing a chemical formula in chemistry can be compared to formulas in maths. Every element has its own symbol, and the way of writing what is contained allows the reader to understand both the primary components and finished products.

How to Write Chemical Compounds Formulas

The process of writing chemical formulas is guided by a set of rules, and you need to understand them well:

  • Prefixes Used for Writing the Number of Atoms in Chemical Equations

When presenting prefixes for atoms in formulas, you should use Greek numbers. Here are some of them:

  1. Mono-
  2. Di-
  3. Tri-
  4. Tetra-
  5. Penta-

If you take the example of acids, each ion is attached to hydrogen atom. So, naming such a compound requires the use of the prefix “hydro-.”

When writing formulas for matter featuring covalent compounds, the chemical formula writer has to write it as a molecular formula. This rule is applied here because every compound works as a separate molecule. Indeed, you should put down the first element of the covalent compound in full but when it comes to writing the second one; a suffix “ide” is added at the end. A good example is “Nitrogen Dioxide.”

  • Writing Down the First Element Symbolically

Another essential component that you need to grasp on how to write chemical formulas is symbols for the elements. One of the best ways to identify the right symbol is referring to the periodic table. For example, the K element is the symbol for potassium, while Mg is used for magnesium in the periodic table.

If you present the name such as Lithium nitride (Li3N), the first element, which is its chemical symbol, is lithium Li.

  • Writing Down the Second Element

When writing the second element’s name, you should finish using the suffix “ide” if dealing with a covalent compound. Take the example of Dinitrogen hexafluoride. Fluoride is the second element, and you can establish the number of atoms by checking the prefixes. In this case, it is “Hexa,” implying there are six atoms of fluoride.

How to Write Chemical Formulas for Ionic Compounds

If you have an ionic compound, how do you write its formula? The secret to getting it right is following the rules for writing molecular formulas. Here is a demonstration:

  • What is the Chemical Symbols for Anions and Cations?

Ionic compounds can have anions (negative ions) and cations (positive ions). When writing ionic formulas, cations are denoted using the element name, but anions go with the suffix “ide” at the end of the element. Again it is important to note that cations, the positive ions, are written first, and anions take the second element in a compound. Check the example below, and see the way cations and anions are presented in line with the rules for writing molecular formulas.

K2S – Here, the compound is made of potassium and sulfur. Potassium is a cation (+2) and, therefore, comes first. On the other hand, Sulfur is an anion (-2) and comes as the second element. It also ends with “ide”.

Seek Help from a Chemistry Homework Writer

As you can see from the demonstrations above, how to make chemical formulas can be really fun if you have good understanding of different chemicals. However, we must indicate that a lot of college students still find formula writing chemistry a serious challenge. So, if you are finding it challenging to complete the assignment too, know that you are not alone, but it is not the time to give up because writing assistance is only a click away.

Some students find the task tough because they are poor in chemistry, while others have competing tasks to finish simultaneously. Even those with some skills on how to write chemical formulas for ionic compounds still prefer seeking professional help with homework. No matter the reason making it hard for you to do the chemistry assignment, our expert writing assistance can help you in getting it done fast.

Our expert writing help is offered by expert writers with years of experience handling similar types of chemistry academic assignments. Therefore, they guarantee you quality work and top grades with the assignment. Our chemistry homework help is also cheap, and all you need is to visit our site and place your order. Do not get stressed wondering, “can someone do my homework” because our professionals guarantee you top-notch work!


How do you write chemical formulas step by step?

Here is a step-by-step guide on how to write a chemical formula;

  1. Identify the elements that are given in the chemical structure
  2. Identify the number of atoms in each element
  3. Write a symbol for each element
  4. Balance the equation

When writing a chemical formula, what goes first?

When writing a chemical formula, the element with the positive charge, known as a cation, should go first, while the component with the negative charge, known as an anion, should follow. That helps to have a clear picture of the elements that are involved in the compounds.

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