Reactivity of Main Group Elements with Oxygen and Halogens for JEE

Chemical compounds known as oxides include one or more oxygen atoms along with another element (e.g. Li₂O). The term "oxide" refers to a binary compound containing oxygen and another element, such as CO₂, SO₂, CaO, CO, ZnO, BaO₂ and water. Since oxygen is combined with just one other element in these substances, they are referred to as oxides. Oxides are divided into acidic, basic, amphoteric and neutral categories based on their acid-base properties.

Group 17's halogens, which are non-metal elements, become less reactive as we move down the group. Group 17 contains the elements fluorine, chlorine, bromine and iodine. Halides are binary compounds in which the halogen atom makes up one portion and an element the other. One or more halogens are present in organic halide compounds, which are a subclass of synthetic and organic substances. Calcium chloride, silver chloride, potassium iodide, sodium chloride, potassium chloride, iodoform, chlorine fluoride, organohalides, bromoethane and other halide compounds are some examples.

Reactivity of Main group Elements with Oxygen 

1. Reaction of Nitrogen with Oxygen: Oxygen and nitrogen combine to generate a variety of oxides with oxidation states ranging from +1 to +5. Except for N₂O₅, which is a solid at normal temperature, all of these oxides are gases. Below are the nitrogen oxides:

NO, N₂O, N₂O₃, NO₂, N₂O₅

The nitrogen oxides are acidic (because they are nonmetal oxides).

2. Reactivity of Sulphur with Oxygen: The only common sulphur oxides are sulphur dioxide (SO₂) and sulphur trioxide (SO₃).

$\mathrm{S}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{~g}) \xrightarrow{\Delta}\mathrm{SO}_{2}(\mathrm{~g})$
Oxoacids and the oxides are created when sulphur and oxygen react. They are all oxidising agents. The major function of SO2 is to create SO3, which when combined with water, produces sulfuric acid. The subsequent reactions are displayed:

$\begin{align} &2 \mathrm{SO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \rightleftarrows 2 \mathrm{SO}_{3}(\mathrm{~g}) \\ & \mathrm{SO}_{3}(\mathrm{~g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{l}) \rightarrow \mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq}) \end{align}$

3. Reactivity of Halogens with Oxygen: The halogens and oxygen react, but many of the resultant compounds are unstable and survive very briefly. They have structures that range from X₂O through X₂O₇, where X stands for a halogen. They can connect with several oxygen atoms simultaneously, thanks to their expanded octets.

Fluorine, that is the most electronegative, takes on the -1 oxidation state. Oxygen fluoride, often known as OF₂, is a compound made of fluorine and oxygen. Other halogens also produce a number of oxides mentioned below:

Reactivity of Main Group Elements with Halogens

1. Reactivity of Sulphur with Halogen: Except for iodine, sulphur directly interacts with all other halogens. It spontaneously reacts with fluorine to produce the colourless, inert gas sulphur hexafluoride, also known as SF₆. It can also produce SF₄, a fluorinating compound. The scarlet liquid SCl₂, which is created when sulphur and chlorine combine, is used to create the deadly mustard gas. The following reaction is displayed:

$3 \mathrm{SF}_{4}+4 \mathrm{BCl}_{3} \rightarrow 4 \mathrm{BF}_{3}+3 \mathrm{SCl}_{2}+3 \mathrm{Cl}_{2}$

2. Reactivity of Halogens with Halogens: Halogens can combine with other halogens to generate compounds (interhalogens). They are denoted by the symbol XY, where X and Y stand for two distinct halogens. IBr and BrCl are a couple of examples of this kind of molecule. Additionally, they can create polyatomic compounds like XY₃, XY₅ and XY₇, which are analogous to molecules like IF₃, BrF₅ and IF₇. The majority of interhalogen substances, like CIF₃ and BrF₃ are highly reactive.

3. Reactivity of Carbon with Halogen: The typical formula for halides is MX₄, which may be formed by 14 elements (CCl₄, SiCl₄, GeCl₄, SnCl₄, PbCl₄). However, some elements including Ge, Sn and Pb, can also create dihalides (MX₂). Since there are no vacant valence d-orbitals available, carbon tetrahalides like CCl₄ cannot be hydrolyzed, while other tetrahalides can.

Brief Note on the Oxides of Halogens 

In order to write a brief note on the oxides of halogens, we must consider following points: 

Reactivity with Oxygen (Formation of Oxides)

• Every component produces oxides. Mostly monoxide and dioxide, with the formulas MO and MO₂, respectively.

• Higher oxidation state elements typically have oxides that are more acidic than elements with lower oxidation states.

• While SnO₂ and Al₂O₃ are amphoteric in nature, the dioxides CO₂, SO₂ and NO₂ are all acidic in nature.

• NO and CO are neutral monoxides.

Reactivity with Halogens (Formation of Halides)

• Their electronegativities are very high.

• Seven valence electrons make them up (one short of a stable octet).

• Particularly, when combined with alkali metals and alkaline earths, they are quite reactive. The most reactive nonmetals are halogens.

• Elemental halogens are poisonous and potentially deadly due to their high reactivity. Up until astatine, which is hazardous due to its radioactivity, toxicity decreases with heavier halogens.

• As you descend the group at STP (standard temperature and pressure), the condition of matter changes. While bromine is a liquid, iodine and astatine are solids, fluorine and chlorine are gases. Moving down the group, the boiling point rises due to the increased Van Der Waals force.

Order of Reactivity of Halogens

With an increase in atomic number, halogens become less reactive. F₂>Cl₂>Br₂>I₂ is the correct sequence of reactivity for the halogens.

F>Cl>Br>I is the sequence of reactivity. It results from the following reasons:

1. The nucleus's attraction to an extra electron decreases as atomic size rises. Reactivity thus declines.

2. The link between halogen and other elements weakens over time, as a result of the drop in electronegativity from F to I. As a result, iodides are least stable. while fluorides are most stable.

Reactivity towards Oxygen

Now we need to answer what is the reactivity order of halogens:

Order of reactivity of oxides of nitrogen is as follows:

NO>N₂O>N₂O₃>N₂O₄>N₂O₅

Order of Reactivity of Oxides of Halogen

Due to the minor difference in electronegativity between halogens and oxygen, the bonds in halogen oxides are primarily covalent; however, as we proceed from F to I, the bond polarity rises. Iodine oxides are more stable than chlorine oxides, whilst bromine oxides are the least stable. The iodine-oxygen bond is stable because it is more polar than the chlorine-oxygen bond, which is stable since it forms numerous bonds with the chlorine atom's d-orbitals. Being in between, bromine lacks both of these qualities. As a result, the stability of halogen oxides declines in the following order: I > Cl > Br > F.

Conclusion

We are well aware of oxygen due to the significant function it plays in maintaining life. Animals would be unable to breathe without oxygen and would therefore perish. Oxygen is crucial for many other chemical reactions in addition to being essential for maintaining life. The most prevalent element in the crust of the earth is oxygen, which accounts for around 20% of the air we breathe. Oxygen forms a number of oxides with other elements in the periodic table, which has its own uses in different fields. The halogens also form halides with other elements of the periodic table, a few of which are discussed above. We have also discussed what is the order of reactivity of oxides of halogens, and the reactivity of oxygen and halogen towards different elements, mainly sulphur, halogens, oxygen, and nitrogen.