Question

Using only the periodic table inside the front cover of the text, write the expected ground-state electron configurations for a. the third element in Group \(5 \mathrm{~A}\). b. element number 116 . c. an element with three unpaired \(5 d\) electrons. d. the halogen with electrons in the \(6 p\) atomic orbitals.

Short answer

The expected ground-state electron configurations for the given elements are: a. Nitrogen: \(1s^2 \ 2s^2 \ 2p^3\) b. Livermorium: \(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^{10} \ 6p^5\) c. Tantalum: \(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^3\) d. Astatine: \(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^{10} \ 6p^5\)

Step-by-step solution

a. The third element in Group 5A

First, we need to find the third element in Group 5A using the periodic table. Group 5A corresponds to elements with an outer electron in the p-block and 5 valence electrons. Counting down three elements in the group gives us nitrogen (N). The electron configuration of nitrogen can be written as follows: \(1s^2 \ 2s^2 \ 2p^3\) So, the expected ground-state electron configuration for the third element in Group 5A is: \(1s^2 \ 2s^2 \ 2p^3.\)

b. Element number 116

We need to find the electron configuration for element number 116. This element is located in the p-block, specifically in the 7th period and has the symbol Lv (Livermorium). The electron configuration of Livermorium can be written as follows: \(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^{10} \ 6p^5\) So, the expected ground-state electron configuration for element number 116 is: \(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^{10} \ 6p^5.\)

c. An element with three unpaired 5d electrons

In this part, we need to find an element with three unpaired 5d electrons. We look for an element whose electron configuration contains the subshell 5d with 3 unpaired electrons. Among the transition metals, the 5d subshell starts filling with Hafnium (Hf, atomic number 72). Counting three elements from Hafnium in the periodic table, we find Tantalum (Ta, atomic number 73). The electron configuration of Tantalum is: \(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^3\) So, the element with three unpaired 5d electrons is Tantalum (\(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^3\)).

d. The halogen with electrons in the 6p atomic orbitals

Finally, we need to find the halogen with electrons in the 6p atomic orbitals. Halogens are found in Group 7A, and their electron configuration ends with p^5 in their outermost shell. Since we are looking for a halogen with electrons in the 6p atomic orbitals, we look for an element in Group 7A that has a 6p^5 configuration at the end. This element is Astatine (At, atomic number 85). The electron configuration of Astatine is: \(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^{10} \ 6p^5\) So, the halogen with electrons in the 6p atomic orbitals is Astatine (\(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^{10} \ 6p^5\)).

Key concepts

ground-state electron configuration

When we talk about the ground-state electron configuration, we're referring to the most stable arrangement of electrons around the nucleus of an atom. This is the configuration in which electrons occupy the lowest possible energy levels in order to achieve stability. Electrons fill up orbitals in a specific order starting from the lowest energy level to higher ones following the Aufbau Principle. Electrons tend to fill the s-orbitals first, followed by p, d, and f successive orbitals.

• The Aufbau Principle: This principle suggests that electrons occupy the lowest energy orbital available.
• The Pauli Exclusion Principle: No two electrons can have the same set of quantum numbers, so an orbital can hold a maximum of two electrons with opposite spins.
• Hund's Rule: Electrons will fill unoccupied orbitals before they pair up in an occupied one to minimize repulsion.

Understanding the electron configuration helps predict the element's chemical properties and reactivity.

periodic table

The periodic table is a comprehensive chart that organizes all known chemical elements based on their atomic number, electron configuration, and recurring chemical properties. It's a valuable tool to categorize and understand elements and predict their behavior.
The table is structured in rows called periods and columns known as groups:

• Periods: There are seven periods in the periodic table. Each new period marks the filling of a higher energy level (shell).
• Groups: The table has 18 groups. Elements in the same group typically have similar properties and the same number of electrons in their outermost shell.

Using the periodic table's layout allows for easy determination of an element's electron configuration.

p-block elements

P-block elements are found on the right side of the periodic table and include groups 13 to 18. These elements have their valence electrons in the p orbital.
Understanding p-block elements is important as they include many common and crucial elements in everyday chemistry.

• P-block elements consist of metals, metalloids, and nonmetals.
• Their oxidation states vary, offering versatile chemistry.
• They play a critical role in organic chemistry, especially the elements of Group 16 (oxygen) and Group 17 (halogens).
• These elements tend to form covalent bonds.

The reactivity of p-block elements can often be predicted by their group positioning, which dictates their electron configuration.

unpaired electrons

Unpaired electrons are those electrons that are alone in an orbital, not paired with another electron of opposite spin. The presence of unpaired electrons in an atom or molecule significantly affects the magnetic and chemical properties of the element.

• Diamagnetic: This occurs when all electrons are paired, and there's no net magnetic moment, resulting in a weak repulsion to magnetic fields.
• Paramagnetic: This is observed when there are unpaired electrons, resulting in a net magnetic moment that is attracted to magnetic fields.
• The presence of unpaired electrons is essential for determining reactivity, especially in transition metals where d or f orbitals are partially filled.

Understanding unpaired electrons allows us to anticipate the behavior of elements when involved in chemical reactions.