Problem 28 - A Complete Resource Book in Chemistry for JEE Main

Question

The electronic configuration of four different elements is given below. Identify the group IV element among these. (a) \([\mathrm{He}] 2 \mathrm{~s}^{1}\) (b) \([\mathrm{Ne}] 3 \mathrm{~s}^{2}\) (c) \([\mathrm{Ne}] 3 \mathrm{~s}^{2} 3 \mathrm{p}^{2}\) (d) \([\mathrm{Ne}] 3 \mathrm{~s}^{2} 3 \mathrm{p}^{5}\)

Step-by-Step Solution

Answer

Option (c) is the Group IV element, which is Silicon (Si).

Step 1: Understanding Group IV Elements

Group IV elements, also known as Group 14 in the periodic table, are characterized by having four electrons in their outer shell. These elements can participate in forming covalent compounds by sharing four electrons.

Step 2: Examining Option (a)

The electronic configuration \( \text{[He]} 2s^1 \) suggests that this element is Lithium (Li), which belongs to Group 1, not Group IV.

Step 3: Examining Option (b)

The electronic configuration \( \text{[Ne]} 3s^2 \) corresponds to Magnesium (Mg), which is part of Group 2 in the periodic table, not Group IV.

Step 4: Examining Option (c)

The electronic configuration \( \text{[Ne]} 3s^2 3p^2 \) corresponds to Silicon (Si). Silicon has four electrons in its outer shell (2 from the \( 3s \) and 2 from \( 3p \)), which places it in Group IV.

Step 5: Examining Option (d)

The electronic configuration \( \text{[Ne]} 3s^2 3p^5 \) suggests that this element is Chlorine (Cl), which belongs to Group 17, not Group IV.

Step 6: Conclusion

Since option (c) \( \text{[Ne]} 3s^2 3p^2 \) represents an element with four valence electrons, it is the Group IV element.

Key Concepts

Periodic Table

The periodic table is a comprehensive chart that organizes all known chemical elements. Each element is arranged based on its atomic number, electron configuration, and recurring chemical properties. By structuring the elements in this way, scientists and students can quickly identify properties shared with other elements.
Each row on the periodic table is called a "period," and each column is known as a "group" or "family." Elements in the same group typically have similar properties and the same number of valence electrons, which explains their similar chemical behavior. For example, Group IV elements share distinctive features because of their similar electron configurations.

Group IV Elements

Group IV elements are found in Group 14 of the periodic table and are often referred to as the carbon family. This group includes carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb). What makes Group IV elements unique is their electron configuration, which features four electrons in their outermost shell.
Having four valence electrons allows these elements to form four covalent bonds, which makes them versatile in creating a variety of compounds. This property is particularly evident in carbon, which forms the basis of organic chemistry. Silicon, similarly, is crucial in the field of electronics as it forms robust semiconductors.

Valence Electrons

Valence electrons are the outermost electrons in an atom and play a critical role in determining how an element will react chemically. In the context of Group IV elements, having four valence electrons means that these atoms can form stable, covalent compounds by sharing all four electrons.
Understanding valence electrons helps in predicting how elements will interact with others to form compounds. Whether through covalent or ionic bonds, an element's reactivity is largely dictated by its valence electrons. Recognizing this pattern enables chemists to anticipate the types of molecules that elements may form.

Covalent Compounds

Covalent compounds are formed when elements share their valence electrons. This type of bond is especially prevalent in Group IV elements, which are adept at sharing their four valence electrons to achieve stable electronic arrangements.
Covalent bonding occurs because the sharing of electrons allows each atom to achieve a full outer shell, promoting a more stable electronic state. These bonds are typically strong and require significant energy to break, which makes covalent compounds robust. Silicon dioxide \(\text{SiO}_2\), for instance, is a covalently bonded compound used in electronics and glass manufacturing.

Elements Identification

Identifying elements based on their electronic configuration is a fundamental skill in chemistry. The electronic configuration reveals an element's placement in the periodic table and its group affiliation. For instance, an electron configuration of \[ \text{[Ne]} 3s^2 3p^2 \] indicates the element is silicon, a Group IV element.
When examining electronic configurations, the highest energy level's s and p orbitals essentially determine the valence electrons of the element. This information lets chemists identify elements' reactive potential and their typical bonding behavior. Learning to decode electronic configurations enables efficient and accurate identification of elements for various chemical applications.