Skip to main content
Ch.5 - Periodicity & Electronic Structure of Atoms
Chapter 5, Problem 105

Give the expected ground-state electron configurations for atoms with the following atomic numbers. (a) Z = 55 (b) Z = 40 (c) Z = 80 (d) Z = 62

Verified step by step guidance
1
Identify the atomic number of the element, which is given as Z = 80. This atomic number tells us that the element has 80 protons and, in a neutral atom, 80 electrons.
Refer to the periodic table to find the element with atomic number 80. This element is Mercury (Hg).
Start filling the electron orbitals in the order of increasing energy levels. The order of filling is based on the Aufbau principle, which can be remembered using the sequence: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p.
Fill the electrons into these orbitals while adhering to the Pauli Exclusion Principle (each orbital can hold a maximum of two electrons with opposite spins) and Hund's Rule (electrons fill empty orbitals of the same energy before pairing up in any one orbital).
The electron configuration for Mercury (Hg) up to the 6s orbital (which is the highest energy level in its ground state) will be: 1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 4s^2, 3d^10, 4p^6, 5s^2, 4d^10, 5p^6, 6s^2, 4f^14, 5d^10.

Verified Solution

Video duration:
2m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Electron Configuration

Electron configuration describes the distribution of electrons in an atom's orbitals. It follows the Aufbau principle, which states that electrons fill orbitals starting from the lowest energy level to the highest. The notation typically includes the principal quantum number, subshell type, and the number of electrons in that subshell, such as 1s² 2s² 2p⁶.
Recommended video:
Guided course
01:33
Electron Configuration Example

Ground State

The ground state of an atom refers to the lowest energy configuration of its electrons. In this state, electrons occupy the lowest available energy levels without any excitation. Understanding ground state configurations is crucial for predicting chemical behavior and reactivity, as excited states can lead to different properties.
Recommended video:
Guided course
01:32
Ground State Electron Configurations

Periodic Table and Atomic Number

The periodic table organizes elements based on their atomic number, which is the number of protons in the nucleus. Each element has a unique atomic number that determines its position in the table and its electron configuration. For example, an element with atomic number 80 is mercury (Hg), and its electron configuration reflects its position in the periodic table.
Recommended video:
Guided course
04:01
Periodic Table History