Question

The electronic configuration of 4 elements \(\mathrm{K}, \mathrm{L}, \mathrm{M}\) and \(\mathrm{N}\) are \(K=1 s^{2} 2 s^{2} 2 p^{1}\) \(L=1 s^{2} 2 s^{2} 2 p^{6}\) \(\mathrm{M}=1 \mathrm{~s}^{2} 2 \mathrm{~s}^{2} 2 \mathrm{p}^{4}\) \(\mathrm{N}=1 \mathrm{~s}^{2} 2 \mathrm{~s}^{2} 2 \mathrm{p}^{3}\) The element that would form a diatomic molecule with double bond is (1) \(\mathrm{K}\) \(\begin{array}{lll}\text { (2) L } & \text { (3) } \mathrm{M} & \text { (4) } \mathrm{N}\end{array}\)

Short answer

Element M

Step-by-step solution

- Understanding Electronic Configuration

The electronic configuration of an element provides information on the arrangement of electrons in its atomic orbitals. Identify the valence shell configuration from the given electronic configurations.

- Identifying Valence Electrons

List the number of valence electrons for each element: - K: 1s² 2s² 2p¹ (3 valence electrons)- L: 1s² 2s² 2p⁶ (8 valence electrons)- M: 1s² 2s² 2p⁴ (6 valence electrons)- N: 1s² 2s² 2p³ (5 valence electrons)

- Determining the Tendency to Form Double Bonds

Double bonds are typically formed by elements that need to share two pairs of electrons to achieve a stable octet configuration. Elements with 6 valence electrons commonly form diatomic molecules with double bonds because they need 2 more electrons to complete their octet; thus they can share two electrons each.

- Applying the Octet Rule

From the valence electrons identified: - K with 3 valence electrons will not form a double bond.- L with 8 (full octet) valence electrons is already stable.- M with 6 valence electrons can form a double bond by sharing 2 more electrons.- N with 5 valence electrons typically forms triple bonds or suffers from instability when trying to form double bonds.

- Conclusion

Element M, with 6 valence electrons, is the most likely to form a diatomic molecule with a double bond to complete its octet.

Key concepts

Valence Electrons

Valence electrons are the electrons in the outermost shell of an atom.
These electrons determine an element's chemical properties and its ability to form bonds.
In our exercise, the valence electrons for the elements K, L, M, and N were:

• K: 3 valence electrons (1s² 2s² 2p¹)
• L: 8 valence electrons (1s² 2s² 2p⁶)
• M: 6 valence electrons (1s² 2s² 2p⁴)
• N: 5 valence electrons (1s² 2s² 2p³)

Knowing the number of valence electrons is crucial for predicting how an element will interact with others. For instance, elements with nearly full or almost empty valence shells are often more reactive.
This is because they readily gain or lose electrons to achieve a stable configuration.

Octet Rule

The octet rule is a chemical rule of thumb that states that atoms tend to combine in such a way that they each have eight electrons in their valence shell.
Elements achieve this configuration by either sharing, gaining, or losing electrons.
This creates a stable, often noble gas-like configuration.
For example:

• K: Only 3 valence electrons, far from a full octet.
• L: Already has a full octet with 8 valence electrons, so it's stable.
• M: Has 6 valence electrons and needs 2 more to complete the octet.
• N: Has 5 valence electrons and needs 3 more for a full octet.

In our specific exercise, element M can achieve its octet by forming a double bond, as it still needs two more electrons.

Double Bonds

Double bonds involve the sharing of two pairs of electrons between two atoms.
This type of bond is common in diatomic molecules, which consist of two atoms.
Elements with six valence electrons, like element M, tend to form double bonds.
This is because they need just two more electrons to complete their octet.
A double bond is depicted using the symbol '=' between two atoms (e.g., O₂ has a double bond in its molecular form).
This bond type provides stability by fulfilling the octet rule for both atoms involved.
Other bond types include single bonds (one pair of shared electrons) and triple bonds (three pairs of shared electrons).
Knowing this helps us conclude that element M, with its six valence electrons, will most likely form a diatomic molecule with a double bond to achieve the stable octet configuration.

Octet Rule

The octet rule is a chemical rule of thumb that states that atoms tend to combine in such a way that they each have eight electrons in their valence shell.
Elements achieve this configuration by either sharing, gaining, or losing electrons.
This creates a stable, often noble gas-like configuration.
For example:

• K: Only 3 valence electrons, far from a full octet.
• L: Already has a full octet with 8 valence electrons, so it's stable.
• M: Has 6 valence electrons and needs 2 more to complete the octet.
• N: Has 5 valence electrons and needs 3 more for a full octet.

In our specific exercise, element M can achieve its octet by forming a double bond, as it still needs two more electrons.

Double Bonds

Double bonds involve the sharing of two pairs of electrons between two atoms.
This type of bond is common in diatomic molecules, which consist of two atoms.
Elements with six valence electrons, like element M, tend to form double bonds.
This is because they need just two more electrons to complete their octet.
A double bond is depicted using the symbol '=' between two atoms (e.g., O₂ has a double bond in its molecular form).
This bond type provides stability by fulfilling the octet rule for both atoms involved.
Other bond types include single bonds (one pair of shared electrons) and triple bonds (three pairs of shared electrons).
Knowing this helps us conclude that element M, with its six valence electrons, will most likely form a diatomic molecule with a double bond to achieve the stable octet configuration.