Is Oxygen a Halogen? (+ 3 Fascinating Facts to Know)

No, oxygen is not a halogen. Oxygen is an element that belongs to the group of chalcogens on the periodic table, specifically Group 16. The chalcogens include oxygen, sulfur, selenium, tellurium, and polonium. ¹

Well, this was just a simple answer. But there are few more things to know about this topic which will make your concept super clear.

So let’s dive right into it.

Why is oxygen not a halogen?

Oxygen is not classified as a halogen because it does not possess the characteristics that define the halogen group of elements. Halogens are a group of highly reactive nonmetallic elements found in Group 17 (Group VIIA) of the periodic table. ²

The halogens include elements such as fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These elements share common properties such as high electronegativity, high reactivity, and the ability to readily form ionic compounds with metals. They also exhibit a tendency to gain an electron to achieve a stable electron configuration. ³

Oxygen, on the other hand, belongs to Group 16 (Group VIA) of the periodic table. Elements in this group are called chalcogens. Oxygen, sulfur (S), selenium (Se), tellurium (Te), and polonium (Po) are examples of chalcogens. ⁴ These elements also have distinct properties, different from halogens.

Oxygen is highly electronegative and can readily form covalent bonds, particularly by sharing electrons with other elements. ⁵ It typically forms compounds by gaining two electrons to achieve a stable electron configuration, whereas halogens tend to gain only one electron. ⁶

In summary, the classification of elements is based on their properties and characteristics, and while oxygen shares some similarities with halogens, it possesses distinct properties that differentiate it from the halogen group.

How is oxygen different from other chalcogens of the group?

Oxygen has some notable differences from the other chalcogens of Group 16. Here are a few ways in which oxygen differs from the other chalcogens:

• Electronegativity: Oxygen is the most electronegative element in the chalcogen group. It has a higher tendency to attract electrons towards itself compared to the other chalcogens. This high electronegativity contributes to oxygen’s reactivity and its ability to form covalent bonds.
• Oxidation States: Oxygen primarily exhibits an oxidation state of -2 in compounds, forming oxides such as water (H2O) and carbon dioxide (CO2). While other chalcogens can also exhibit an oxidation state of -2, they can adopt a wider range of oxidation states in compounds. ⁷ For example, sulfur can have oxidation states of -2, +4, and +6, while selenium and tellurium can have oxidation states ranging from -2 to +6.
• Reactivity: Oxygen is highly reactive and readily participates in redox (reduction-oxidation) reactions. ⁸ It is a powerful oxidizing agent, capable of accepting electrons from other elements. The other chalcogens also exhibit reactivity but to varying degrees. For example, sulfur is known for its reactivity in forming sulfur compounds, while selenium and tellurium are less reactive than sulfur.
• Allotropes: Oxygen has multiple allotropes, meaning it can exist in different forms with distinct physical and chemical properties. The most common form is molecular oxygen (O2), which makes up around 21% of the Earth’s atmosphere. ⁹ Another important allotrope is ozone (O3), which plays a crucial role in the Earth’s ozone layer. ¹⁰ In contrast, the other chalcogens do not have as many well-known allotropes.
• Abundance and Importance: Oxygen is by far the most abundant chalcogen on Earth. It is a key component of the atmosphere, water, and many organic compounds. Its presence is essential for supporting life as we know it, as it is involved in respiration and combustion. While the other chalcogens are also important, they are generally less abundant and have more specialized roles in various applications.

These differences highlight the unique properties and significance of oxygen compared to the other chalcogens in Group 16.

Further reading

Why is Chlorine a Halogen?
Why is Iodine a Halogen?
Why are Halogens So Reactive?
Does water conduct electricity?
Why is Cobalt Magnetic? 

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