Question

The process of successive addition of protons to the nucleus followed by an addition of the same number of electrons to the available orbitals in the sequence of increasing energy to obtain the electronic configuration of many electronic configuration of many electron atom, is known as (a) Pauli's exclusion principle (b) Hund's rule (c) Heisenberg's uncertainty principal (d) Aufbau principle

Short answer

The process described in the question is known as the (d) Aufbau principle.

Step-by-step solution

Understand the Definition

Firstly, comprehend the process described in the question. It is about adding protons to the nucleus and then adding an equal number of electrons to the orbitals in order of increasing energy levels. This process is meant to determine the electronic configuration of many-electron atoms.

Analyze the Options

Now, let's consider each of the given principles or rules to identify which one matches the described process: (a) Pauli's exclusion principle is about the uniqueness of each electron's set of quantum numbers. (b) Hund's rule deals with the filling of electrons in orbitals of the same energy level. (c) Heisenberg's uncertainty principle pertains to the impossibility of simultaneously knowing position and momentum of a particle with absolute precision. (d) Aufbau principle describes the sequential filling of electrons into orbitals from lowest to highest energy.

Match the Description with the Correct Principle

By comparing the process described with the definitions of each principle, it is clear that the Aufbau principle is the one that describes the sequential addition of protons to the nucleus and electrons to the orbitals based on increasing energy levels to obtain the electronic configuration of atoms.

Key concepts

Pauli's Exclusion Principle

The Pauli's exclusion principle is a fundamental concept in quantum mechanics that plays a critical role in determining the electronic structure of atoms. According to this principle, no two electrons in an atom can have the same set of four quantum numbers. These quantum numbers describe the properties of an electron within an atom, including its orbital type, the shape of the orbital, the orientation of the orbital, and the electron’s spin direction.

Simplified, you can think of it as a rule stating that in a single atom, each electron must be unique in its characteristics and no 'electron twin' is allowed. This rule explains why electrons fill orbitals in the way they do, and it is crucial when figuring out the electronic configurations of elements. As an analogy, consider a hotel with rooms (orbitals) on different floors (energy levels) where every room (orbital) can only accommodate two guests (electrons), and each guest must have different outfits (quantum numbers).

Hund's Rule

Hund's rule is another principle that guides the filling of electrons in atoms. It states that electrons will fill degenerate orbitals (orbitals of the same energy level) singly as far as possible before pairing up. This is because electrons are negatively charged and repel each other; by occupying different orbitals, they can minimize their repulsion.

This is akin to passengers on a bus preferring to sit alone in an empty row rather than next to someone else. Only when there are no vacant rows left, will they start sitting next to each other. In the context of orbitals, electrons behave similarly, spreading out to occupy different spaces before pairing up. Understanding Hund's rule aids in predicting the arrangement of electrons in orbitals, and consequently, it helps in sketching the electronic configuration of an atom.

Heisenberg's Uncertainty Principle

Moving away from electron configurations, we delve into the Heisenberg's uncertainty principle, which is one of the key pillars in quantum mechanics. It reveals a fundamental limit to what we can know about the properties of subatomic particles. Specifically, it states that it's impossible to know both the exact position and exact momentum of an electron simultaneously.

Imagine trying to take a perfectly clear photo of a fast-moving car at night; you can either get a sharp image of its position by using a quick shutter speed, but you’ll not capture its speed, or you can get a sense of its speed by using a slow shutter speed, but the car's position will be blurred. This principle doesn't come into play much when figuring out the electronic configuration of an atom, but it's a crucial aspect of understanding the behavior of electrons and atoms on a quantum level.

Electronic Configuration

The electronic configuration is the arrangement of electrons in the orbitals of an atom or molecule. It follows a specific order of filling based on increasing energy levels, which is outlined by the Aufbau principle. This configuration is typically expressed using notations that indicate the energy levels, sublevels, and the number of electrons in each sublevel.

For instance, the electronic configuration of carbon is written as 1s² 2s² 2p², indicating that carbon has two electrons in the first energy level (s orbital), and four electrons in the second energy level, distributed as two in the s orbital and two in the p orbitals. Understanding an element's electronic configuration provides essential insights into its chemical properties and the types of chemical bonds it can form.