Question

Write the valence shell electron configuration of each of the following elements, basing your answer on the element's location on the periodic table. a. rubidium, \(Z=37\) b. barium, \(Z=56\) c. titanium, \(Z=22\) d. germanium, \(Z=32\)

Short answer

The valence shell electron configurations for the given elements are: a. Rubidium (Z=37): \(5s^1\) b. Barium (Z=56): \(6s^2\) c. Titanium (Z=22): \(4s^2 3d^2\) d. Germanium (Z=32): \(4s^2 4p^2\)

Step-by-step solution

Determine the electron configurations

Using the periodic table, find the electron configurations for each of the given elements. a. Rubidium (Z=37): - Located in Period 5, Group 1 (alkali metals), so configuration is [Kr]5s^1 b. Barium (Z=56): - Located in Period 6, Group 2 (alkaline earth metals), so configuration is [Xe]6s^2 c. Titanium (Z=22): - Located in Period 4, Group 4 (transition metals), so configuration is [Ar]4s^2 3d^2 d. Germanium (Z=32): - Located in Period 4, Group 14 (carbon group), so configuration is [Ar]4s^2 3d^10 4p^2

Write the valence shell electron configurations

Look at the highest principal quantum number (n) in each electron configuration to find the valence shell. a. Rubidium (Z=37): - Valence shell: 5 (n=5) - Valence shell electron configuration: 5s^1 b. Barium (Z=56): - Valence shell: 6 (n=6) - Valence shell electron configuration: 6s^2 c. Titanium (Z=22): - Valence shell: 4 (n=4) - Valence shell electron configuration: 4s^2 3d^2 d. Germanium (Z=32): - Valence shell: 4 (n=4) - Valence shell electron configuration: 4s^2 4p^2

Key concepts

Understanding the Periodic Table

The periodic table is an organized arrangement of elements, providing valuable insights into their properties and how they interact with each other. Each element is listed in order of increasing atomic number, which is the number of protons in an atom's nucleus. The table is structured in rows called periods and columns known as groups or families.

Elements in the same group often share similar chemical properties because they have the same number of valence electrons. The position of an element on the periodic table thus becomes a quick and powerful tool to predict its behavior in chemical reactions. For example, rubidium, with an atomic number of 37, falls into Group 1, indicating it has a single valence electron in its outermost shell, leading to its reactivity similarly to other alkali metals.

Electron Configuration

Electron configuration describes the distribution of electrons in atoms' orbitals. It's based on a set of principles, including Aufbau's principle, Hund's rule, and the Pauli exclusion principle. These rules help predict the electron arrangements in atoms' orbitals and, more importantly, in their valence shells.

The valence shell is the outermost shell of an atom and determines how an element will engage in chemical bonds. For instance, germanium has the electron configuration [Ar]4s^2 3d^10 4p^2. The valence electrons, found in the highest energy levels (in this case, 4s and 4p orbitals), dictate how it will bond with other elements. Understanding electron configurations is pivotal in chemistry because it underpins the behavior of elements in various reactions.

Principal Quantum Number

The principal quantum number, denoted as 'n', indicates the relative size and energy level of an orbital where an electron is likely to be found. It can assume any positive integer value, and the value of 'n' increases as the electron's energy and its average distance from the nucleus increase.

In general, the higher the principal quantum number, the higher the energy level and the farther the electron is from the nucleus. For instance, titanium has a valence shell electron configuration of 4s^2 3d^2, meaning its valence electrons are in the fourth shell (n=4). This also impacts the element's reactivity since valence electrons dictate an element's ability to form bonds with other atoms. By examining the highest value of 'n' in an electron configuration, we can identify which electrons are in the valence shell, and thus, play a significant role in chemical interactions.