Question

Identify the following three elements. a. The ground-state electron configuration is \([\mathrm{Kr}] 5 s^{2} 4 d^{10} 5 p^{4}\) b. The ground-state electron configuration is \([\mathrm{Ar}] 4 s^{2} 3 d^{10} 4 p^{2}\) c. An excited state of this element has the electron configuration 1\(s^{2} 2 s^{2} 2 p^{4} 3 s^{1}\)

Short answer

The identified elements are: a. Tellurium (Te) - Ground state electron configuration b. Germanium (Ge) - Ground state electron configuration c. Fluorine (F) - Excited state electron configuration

Step-by-step solution

Identify element for configuration a

For configuration a, \([\mathrm{Kr}] 5 s^{2} 4 d^{10} 5 p^{4}\), we first need to determine the atomic number of Kr. Kr has an atomic number of 36. Now, we add the electrons from the additional subshells: 36 (from Kr) + 2 (from \(5s^2\)) + 10 (from \(4d^{10}\)) + 4 (from \(5p^4\)) = 52 The element with atomic number 52 is Tellurium (Te).

Identify element for configuration b

For configuration b, \([\mathrm{Ar}] 4 s^{2} 3 d^{10} 4 p^{2}\), we first need to determine the atomic number of Ar. Ar has an atomic number of 18. Now, we add the electrons from the additional subshells: 18 (from Ar) + 2 (from \(4s^2\)) + 10 (from \(3d^{10}\)) + 2 (from \(4p^2\)) = 32 The element with atomic number 32 is Germanium (Ge).

Identify element for excited state configuration c

For the excited state configuration c, \(1s^{2} 2s^{2} 2p^{4} 3s^{1}\), we sum up the number of electrons: 2 (from \(1s^2\)) + 2 (from \(2s^2\)) + 4 (from \(2p^4\)) + 1 (from \(3s^1\)) = 9 The element with atomic number 9 is Fluorine (F). We can conclude that: a. Tellurium (Te) - Ground state electron configuration b. Germanium (Ge) - Ground state electron configuration c. Fluorine (F) - Excited state electron configuration

Key concepts

Ground State

In chemistry, the ground state of an atom refers to the lowest energy configuration of its electrons. It is the most stable state for an atom and generally corresponds to the situation in which electrons occupy the lowest available energy levels. This arrangement is guided by the principles of quantum mechanics: the Aufbau principle, Hund's rule, and the Pauli Exclusion Principle.
For example, in the exercise provided, configurations for Tellurium and Germanium are given in their ground states. Tellurium's ground-state configuration is \(\mathrm{[Kr]}\ 5\ s^{2}\ 4\ d^{10}\ 5\ p^{4}\), while Germanium's is \(\mathrm{[Ar]}\ 4\ s^{2}\ 3\ d^{10}\ 4\ p^{2}\). These configurations indicate how electrons are distributed across the various sub-shells in their lowest energy states. The electrons fill the 1s orbital first, then the 2s, followed by 2p, 3s, and so forth, as per increasing energy levels.

Excited State

An excited state occurs when electrons in an atom have absorbed energy and moved to a higher energy level, leaving lower-energy levels partially filled. This state is generally unstable, and atoms tend to release the absorbed energy and return to their ground state.
For instance, in the exercise, an excited state is presented for Fluorine. Its electron configuration in this state is\(1s^{2} 2s^{2} 2p^{4} 3s^{1}\).Normally, all electrons would fill the 1s, 2s, and 2p orbitals before entering the next level (3s). However, one of the 2p electrons has been excited to the 3s orbital, resulting in this particular configuration.
Given that excited states are temporary, electrons will eventually release energy, often in the form of light, and 'fall' back to their ground state configuration.

Atomic Number

The atomic number is a fundamental property of a chemical element and is defined as the number of protons in the nucleus of an atom. It essentially dictates the identity of an element, as each element has a unique atomic number.
To identify the elements in the exercise, one can add up the total number of electrons provided by the electron configurations. For instance, Tellurium has an atomic number of 52, determined by adding 36 (from Krypton [Kr] core configuration) plus the electrons in the additional orbitals. Similarly, Germanium's atomic number is 32, and Fluorine's is 9. It's crucial to calculate atomic numbers correctly, since they guide us not only to an element’s chemical properties but also its placement in the periodic table.

Chemical Elements

Chemical elements are pure substances consisting of only one type of atom, each characterized by a unique number of protons in their atomic nuclei. They are the building blocks of matter and are organized systematically in the periodic table based on their atomic structures and properties.
In the exercise we examined, elements like Tellurium, Germanium, and Fluorine were identified by interpreting their electron configurations. Tellurium is a metalloid, crucial in various industrial applications such as thermoelectric devices. Germanium is another metalloid, often used in semiconductor technology. Fluorine, on the other hand, is a highly reactive, non-metallic element used widely in toothpaste and Teflon coating.

• Understanding chemical elements involves recognizing their distinct electron configurations and atomic numbers.
• These factors help predict chemical behavior and potential reactivity in different environments.

By grasping these concepts, you can better understand not only the nature of each element but also their diverse applications in science and industry.