You are viewing the article How to Calculate Atomic Mass at Thptlaihoa.edu.vn you can quickly access the necessary information in the table of contents of the article below.
Calculating the atomic mass of an element is an essential skill in the field of chemistry. The atomic mass, also known as the atomic weight, of an element is the weighted average mass of all the naturally occurring isotopes of that element. It provides crucial information about the element’s identity and its properties. In this guide, we will explore the step-by-step process of calculating the atomic mass of an element using the information provided on the periodic table. From understanding isotopes to implementing mathematical calculations, we will delve into the fundamental concepts and practical methods required to accurately determine the atomic mass of any given element.
This article is co-authored by a team of editors and trained researchers who confirm the accuracy and completeness of the article.
The wikiHow Content Management team carefully monitors the work of editors to ensure that every article is up to a high standard of quality.
This article has been viewed 86,092 times.
Atomic mass is the total mass of protons, neutrons, and electrons in an atom or molecule. [1] XResearch Source However, the mass of the electron is often ignored and not included in the formula because this value is very small. [2] XResearch Source Atomic mass is often used to refer to the average atomic mass of all isotopes of an element, although such a usage is academically incorrect. The average atomic mass is actually the relative atomic mass, also known as the atomic weight , of an element. [3] XResearch Source Atomic weight is determined based on the average mass of natural isotopes of the same element. Chemists need to distinguish these two types of atomic mass in their calculations, because taking the wrong atomic mass value can lead to errors when calculating the reaction efficiency.
Steps
Find the atomic mass on the periodic table
![Image titled 1083156 1](https://www.wikihow.com/images_en/thumb/0/0b/1083156-1.jpg/v4-728px-1083156-1.jpg)
- The atomic mass unit indicates the mass of one mp of an element or molecule in grams . Therefore, this is a very useful property in practical calculations because it allows us to easily convert between the mass and the number of mps of a given number of atoms or molecules in the same state.
![Image titled 1083156 2](https://www.wikihow.com/images_en/thumb/1/10/1083156-2.jpg/v4-728px-1083156-2.jpg)
- It should be noted that the relative atomic mass given in the periodic table is the average mass of that element. Elements with multiple isotopes – isotopes are different variations of the same element and each has a different mass since they will have more or less one to a few neutrons in the nucleus of the element. atom. [5] XSource of study Therefore, the relative atomic mass given in the periodic table only represents the average mass of the atoms of an element, not the mass of an atom of that element. .
- Relative atomic mass, as stated in the periodic table, is used to calculate the mass mp of atoms and molecules. Technically, the atomic mass, when expressed in units of amu as shown in the periodic table, has no units. However, multiplying the atomic mass by 1g/mp yields a quantity that can be used to calculate the mass mp – the mass (in grams) of one mp of atoms – of an element.
![Image titled 1083156 3](https://www.wikihow.com/images_en/thumb/5/57/1083156-3.jpg/v4-728px-1083156-3.jpg)
- Since this is an average of many isotopes, the value given in the periodic table is not an exact atomic mass value for any one atom of that element.
- The atomic mass of individual atoms must be calculated by considering the exact number of protons and neutrons in each atom.
Calculate the atomic mass of a single atom
![Image titled Calculate Atomic Mass Step 1](https://www.wikihow.com/images_en/thumb/3/35/Calculate-Atomic-Mass-Step-1-Version-2.jpg/v4-728px-Calculate-Atomic-Mass-Step-1-Version-2.jpg)
- Consider the carbon atom. Carbon always has 6 protons, so the atomic number of carbon is 6. We can also look in the periodic table, in the box for carbon (C), we have the number “6” above the chemical symbol (C). , which denotes that carbon’s atomic number is six.
- It should be noted that the atomic number of an element does not directly affect the relative atomic mass given in the periodic table. Although it may seem that the atomic mass of a substance is twice the atomic number of that substance, especially for elements at the top of the periodic table, it is not possible to calculate the atomic mass by doubling the atomic number. atom.
![Image titled Calculate Atomic Mass Step 2](https://www.wikihow.com/images_en/thumb/7/74/Calculate-Atomic-Mass-Step-2-Version-2.jpg/v4-728px-Calculate-Atomic-Mass-Step-2-Version-2.jpg)
- The number of neutrons can be determined based on the isotopic indication of the element. For example, carbon 14 is a naturally occurring isotope of carbon-12. An isotope is indicated by a number written above the element symbol: 14 C. The number of neutrons is calculated by subtracting the number of protons from the isotope indicator: 14 – 6 = 8 protons.
- Suppose we are considering a carbon atom with 6 neutrons ( 12 C). It is the most common isotope of carbon, accounting for about 99% of the carbon atoms present in nature. [7] XResearch Source However, 1% of carbon atoms contain 7 neutrons ( 13 C). Other forms of carbon with more or less than 6 or 7 neutrons exist only in very small quantities.
![Image titled Calculate Atomic Mass Step 4](https://www.wikihow.com/images_en/thumb/2/27/Calculate-Atomic-Mass-Step-4-Version-2.jpg/v4-728px-Calculate-Atomic-Mass-Step-4-Version-2.jpg)
- The carbon atom has 6 protons + 6 neutrons = 12. The atomic mass of this carbon is 12. On the other hand, if it were the isotope carbon-13 , the atom would have 6 protons + 7 neutrons = 13 , in this case the atomic mass would be 13.
- The net atomic mass of carbon-13 is 13.003355 [8] XResearch Source , this value is more accurate because it is determined experimentally.
- The atomic mass of an element is very close to the isotope indicator number. In simple calculations, we can treat the number of isotopic indicators as equal to the atomic mass. When determined experimentally, the atomic mass will be slightly larger than the isotope indicator number because at this time the very small mass of the electrons is also taken into account.
Calculate the relative atomic mass of an element
![Image titled Calculate Atomic Mass Step 4](https://www.wikihow.com/images_en/thumb/6/6b/Calculate-Atomic-Mass-Step-4-Version-3.jpg/v4-728px-Calculate-Atomic-Mass-Step-4-Version-3.jpg)
- For the purposes of this article, let’s assume we are dealing with isotopes of carbon-12 and carbon-13.
![Image titled Calculate Atomic Mass Step 5](https://www.wikihow.com/images_en/thumb/b/bb/Calculate-Atomic-Mass-Step-5-Version-3.jpg/v4-728px-Calculate-Atomic-Mass-Step-5-Version-3.jpg)
- The carbon-12 abundance is 99% and the carbon-13 abundance is 1%. Other isotopes of carbon do exist, but in very small amounts, so for this example we can ignore their values.
![Image titled Calculate Atomic Mass Step 6](https://www.wikihow.com/images_en/thumb/4/4f/Calculate-Atomic-Mass-Step-6-Version-3.jpg/v4-728px-Calculate-Atomic-Mass-Step-6-Version-3.jpg)
- In the example under consideration, the sample contains carbon-12 and carbon-13. If carbon-12 makes up 99% of the sample, and carbon-13 makes up 1% of the sample, multiply 12 (atomic mass of carbon-12) by 0.99 and multiply 13 (atomic mass of carbon-13) by 0, 01.
- Reference books will likely have percentage information based on known isotopes of an element. Most chemistry textbooks have a table of this data at the end of the book. The mass spectrometer can also give results on the ratio of isotopes in the sample.
![Image titled Calculate Atomic Mass Step 7](https://www.wikihow.com/images_en/thumb/f/f0/Calculate-Atomic-Mass-Step-7-Version-3.jpg/v4-728px-Calculate-Atomic-Mass-Step-7-Version-3.jpg)
- In our example, we have 12 x 0.99 = 11.88 with carbon-12 and 13 x 0.01 = 0.13 with carbon-13. So the relative atomic mass in this example is 11.88 + 0.13 = 12.01 .
Things you need
- Chemistry reference book
- Computer
This article is co-authored by a team of editors and trained researchers who confirm the accuracy and completeness of the article.
The wikiHow Content Management team carefully monitors the work of editors to ensure that every article is up to a high standard of quality.
This article has been viewed 86,092 times.
Atomic mass is the total mass of protons, neutrons, and electrons in an atom or molecule. [1] XResearch Source However, the mass of the electron is often ignored and not included in the formula because this value is very small. [2] XResearch Source Atomic mass is often used to refer to the average atomic mass of all isotopes of an element, although such a usage is academically incorrect. The average atomic mass is actually the relative atomic mass, also known as the atomic weight , of an element. [3] XResearch Source Atomic weight is determined based on the average mass of natural isotopes of the same element. Chemists need to distinguish these two types of atomic mass in their calculations, because taking the wrong atomic mass value can lead to errors when calculating the reaction efficiency.
In conclusion, calculating the atomic mass provides valuable information about an element’s properties and its composition. The atomic mass is determined by considering the abundance of each isotope present in a given element and their respective masses. This calculation is done by multiplying the mass of each isotope by its abundance, which is expressed as a decimal or percentage. By summing up the masses of the isotopes, we can find the average atomic mass. This value is usually close to the whole number of the element’s most abundant isotope, but it may have decimal places due to the existence of different isotopes. The atomic mass is crucial in chemistry and other scientific fields as it helps in determining the amount of a substance needed for reactions or studying the behavior of elements in various conditions. It also aids in identifying the isotopic composition of an element, which can have biological, environmental, and industrial implications. Overall, understanding how to calculate atomic mass allows scientists to make accurate predictions and calculations in their research and helps advance our knowledge of the atomic world.
Thank you for reading this post How to Calculate Atomic Mass at Thptlaihoa.edu.vn You can comment, see more related articles below and hope to help you with interesting information.
Related Search:
1. What is atomic mass and why is it important in chemistry?
2. How to find the atomic mass of an element using the periodic table.
3. Is the atomic mass the same as the mass number?
4. How to calculate atomic mass from isotopic abundances and masses.
5. What units are used to express atomic mass?
6. Can atomic mass differ for different samples of the same element?
7. How is average atomic mass calculated for elements with multiple isotopes?
8. How does atomic mass play a role in chemical reactions?
9. Are there any exceptions or limitations to calculating atomic mass?
10. Does atomic mass affect an element’s physical properties?