In the modern periodic table, the elements are listed in order of increasing atomic number. The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present). The number of protons determines how many electrons surround the nucleus, and it is the arrangement of these electrons that determines most of the chemical behavior of an element.
- Name: Oxygen Symbol: O Atomic Number: 8 Atomic Mass: 15.9994 amu Melting Point:-218.4 °C (54.750008 K, -361.12 °F) Boiling Point:-183.0 °C (90.15 K, -297.4 °F) Number of Protons/Electrons: 8 Number of Neutrons: 8 Classification: Non-metal Crystal Structure: Cubic Density @ 293 K: 1.429 g/cm 3 Color: colorless Atomic Structure.
- 2020-11-21 by Nick Connor Atomic Mass of Oxygen Atomic mass of Oxygen is 15.9994 u.
In a periodic table arranged in order of increasing atomic number, elements having similar chemical properties naturally line up in the same column (group). For instance, all of the elements in Group 1A are relatively soft metals, react violently with water, and form 1+ charges; all of the elements in Group 8A are unreactive, monatomic gases at room temperature, etc. In other words, there is a periodic repetition of the properties of the chemical elements with increasing mass.
8 on the Periodic Table of the Elements is a colorless gas that makes up 21 percent of Earth's atmosphere. Because it's all around, oxygen is easy to dismiss as dull and inert; in fact. Name: Oxygen Symbol: O Atomic Number: 8 Atomic Mass: 15.9994 amu Melting Point:-218.4 °C (54.750008 K, -361.12 °F) Boiling Point:-183.0 °C (90.15 K, -297.4 °F) Number of Protons/Electrons: 8 Number of Neutrons: 8 Classification: Non-metal Crystal Structure: Cubic Density @ 293 K: 1.429 g/cm 3 Color: colorless Atomic Structure. Atomic and molecular oxygen are chemical species derived from the chemical element, oxygen which has the atomic number 8. The difference between atomic oxygen and molecular oxygen is that atomic oxygen is highly reactive and does not exist in the atmosphere as it is whereas molecular oxygen is less reactive and exists in the atmosphere as it is.
In the original periodic table published by Dimitri Mendeleev in 1869, the elements were arranged according to increasing atomic mass— at that time, the nucleus had not yet been discovered, and there was no understanding at all of the interior structure of the atom, so atomic mass was the only guide to use. Once the structure of the nucleus was understood, it became clear that it was the atomic number that governed the properties of the elements.
The key difference between atomic oxygen and molecular oxygen is that the atomic oxygen is highly reactive and does not exist in the atmosphere as it is whereas the molecular oxygen is less reactive and exists in the atmosphere as it is. Moreover, atomic oxygen is a free radical having the symbol O(3P) while the molecular oxygen is a diatomic oxygen having the symbol O2.
Oxygen is a chemical element having the atomic number 8. But when we refer to oxygen in common use, we are talking about molecular oxygen that we breathe. It has two oxygen atoms bonded to each other via covalent bond. Atomic oxygen has one oxygen atom. Therefore, it cannot exist as an individual chemical species because of its high reactivity.
CONTENTS
1. Overview and Key Difference
2. What is Atomic Oxygen
3. What is Molecular Oxygen
4. Side by Side Comparison – Atomic Oxygen vs Molecular Oxygen in Tabular Form
5. Summary
What is Atomic Oxygen?
Atomic oxygen is a very reactive chemical species having the symbol O(3P). It is a free radical. This means atomic oxygen has an unpaired electron that makes this atom highly reactive. Therefore, this atom does not exist naturally for even a short period; it tends to react with other chemical elements or compounds to become stable by pairing its unpaired electron.
Atomic No Of Oxygen
However, in outer space, about 96% of oxygen exists as atomic oxygen because there UV radiation results in a low earth orbits atmosphere. This chemical species plays a major role in corrosion in space. Corrosion in space is the corrosion of materials occurring in outer space.
What is Molecular Oxygen?
Molecular oxygen is diatomic oxygen having the symbol O2. It contains two oxygen atoms bonded to each other via covalent bonding. There is a double bond between these two atoms. Since the two oxygen atoms have eight electrons around them, the oxygen molecule is less reactive.
Figure 02: Formation of Molecular Oxygen
Therefore, this chemical species exist in the atmosphere itself. Our atmosphere has about 21% molecular oxygen. This amount of oxygen is essential for all the organisms for their respiration. It exists as a colorless gas and the boiling point is −183 °C.
What is the Difference Between Atomic Oxygen and Molecular Oxygen?
Atomic oxygen is a very reactive chemical species having the symbol O(3P). It does not exist naturally for even a short period, but in outer space, it is the predominant form of oxygen. Moreover, it is highly reactive. Molecular oxygen is diatomic oxygen which has the symbol O2. It exists as itself in our atmosphere (about 21%). In addition, it is less reactive.
Summary – Atomic Oxygen vs Molecular Oxygen
Atomic and molecular oxygen are chemical species derived from the chemical element, oxygen which has the atomic number 8. The difference between atomic oxygen and molecular oxygen is that atomic oxygen is highly reactive and does not exist in the atmosphere as it is whereas molecular oxygen is less reactive and exists in the atmosphere as it is.
Reference:
1. “Allotropes of Oxygen.” Wikipedia, Wikimedia Foundation, 26 May 2018. Available here
2. Leenhouts, Doug. “The Differences of Oxygen & Oxygen Gas.” Sciencing, 24 Apr. 2017. Available here
Image Courtesy:
1.’Electron shell 008 Oxygen – no label’By Pumbaa (original work by Greg Robson) (CC BY-SA 2.0 uk) via Commons Wikimedia
2.’Figure 02 01 09’By CNX OpenStax,(CC BY 4.0) via Commons Wikimedia