Problem 43 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

The electronegativity of the following elements increases in the order (a) \(\mathrm{C}, \mathrm{N}, \mathrm{Si}, \mathrm{P}\) (b) \(\mathrm{N}, \mathrm{Si}, \mathrm{C}, \mathrm{P}\) (c) Si, P, C, N (d) \(\mathrm{P}, \mathrm{Si}, \mathrm{N}, \mathrm{C}\)

Step-by-Step Solution

Answer

Option (c) \( \mathrm{Si}, \mathrm{P}, \mathrm{C}, \mathrm{N} \) is correct.

Step 1: Understanding Electronegativity

Electronegativity is the ability of an atom to attract electrons toward itself in a chemical bond. Generally, electronegativity increases from left to right across a period and decreases down a group in the periodic table.

Step 2: Identify Elements Location

Find the position of the elements in the periodic table: Carbon (C) and Nitrogen (N) are in the same period, with Nitrogen being to the right. Silicon (Si) and Phosphorus (P) are also in the same period, with Phosphorus being to the right.

Step 3: Compare Electronegativity Trends

Among the given elements: \( \mathrm{N} > \mathrm{C} \) (because both are in the same period, but N is to the right and higher in the group). Similarly, \( \mathrm{P} > \mathrm{Si} \). Generally, \( \mathrm{N} > \mathrm{C} > \mathrm{P} > \mathrm{Si} \).

Step 4: Match with Given Options

Compare the determined trend of electronegativity \( \mathrm{Si}, \mathrm{P}, \mathrm{C}, \mathrm{N} \) to the provided options:- Option (a) \( \mathrm{C}, \mathrm{N}, \mathrm{Si}, \mathrm{P} \) is incorrect.- Option (b) \( \mathrm{N}, \mathrm{Si}, \mathrm{C}, \mathrm{P} \) is incorrect.- Option (c) \( \mathrm{Si}, \mathrm{P}, \mathrm{C}, \mathrm{N} \) is correct.- Option (d) \( \mathrm{P}, \mathrm{Si}, \mathrm{N}, \mathrm{C} \) is incorrect.

Key Concepts

Periodic Table

The periodic table is a powerful tool for chemists everywhere. It organizes all known elements in an intuitive, structured way. Every element is listed by increasing atomic number, usually across rows called periods. It also groups elements with similar chemical behaviors into columns known as groups. This setup helps predict how an element might look or behave, based on its placement.

Elements over time were placed into this table to showcase their shared properties. For instance, elements like helium, neon, and argon (noble gases) are together since they don't like to react with other elements. The periodic table isn't just a neat list; it's a deep dive into chemical behavior. By understanding it, you unlock a guide to elements' properties and behaviors.

Periodic Trends

Periodic trends are patterns seen across the periodic table that tell us how elements are likely to react or bond with others. The periodic table is not just about organizing elements; it also reveals important properties like electronegativity, atomic radius, and ionization energy.

* **Electronegativity** is a key periodic trend. It describes how strongly an element can attract electrons during chemical bonding. Typically, as you move from left to right across a period, electronegativity increases. This is because elements to the right, like fluorine or oxygen, are more eager to get electrons. * As you go down a group, electronegativity often decreases. This is because electrons are further away from the atomic center, reducing an atom’s pull on them.

Understanding these trends is crucial. They help chemists predict reactions and create new compounds by knowing how strongly atoms attract electrons.

Chemical Bonding

Chemical bonding is the attraction between atoms that allows them to form compounds. Bonds are what sticks atoms together, making substances like water or carbon dioxide. There are several types of bonds, and each has unique properties.

• Covalent bonding occurs when two atoms share electrons. It's common between non-metal atoms. For example, in a water molecule, the hydrogen atoms share their electrons with oxygen.
• Ionic bonding is where one atom gives up electrons to another. This usually happens between metals and non-metals, like in salt (sodium chloride).
• Metallic bonding is seen in metals, where electrons are not bound to any one atom and can move freely, giving metals their conductivity and malleability.

In any bond, atoms seek stability, often reaching a full outer electron shell, akin to the noble gases. The concept of electronegativity becomes essential here, as it determines how strongly atoms pull on shared or transferred electrons in these bonds. Understanding chemical bonding is key to understanding the vast array of materials around us and their interactions.