Electronic Structure: Shells: Videos & Practice Problems

In atomic structure, the shell, represented by the variable n, indicates the grouping of electrons around the nucleus, correlating to their potential energy. As n increases, both the size and energy level of atomic orbitals rise, linking to the periodic table's rows. Currently, there are seven rows, but future discoveries may lead to new elements and additional rows. The shell number can range from 1 to infinity, emphasizing the dynamic nature of the periodic table and the potential for ongoing scientific exploration.

Electronic Structure: Shells Concept 1

In atomic structure, the concept of shells, represented by the variable n, refers to the grouping of electrons that surround the nucleus of an atom. These shells are crucial as they relate to the potential energy of the electrons, indicating their energy of position. As the value of n increases, both the size and energy level of the atomic orbitals also increase. This relationship is directly tied to the periods or rows of the periodic table, where each period corresponds to a specific shell. For instance, the first row of the periodic table aligns with shell 1, the second row with shell 2, and so forth, up to the seventh row, which corresponds to shell 7.

Currently, the periodic table consists of seven rows, but it is important to recognize that it is a dynamic entity. Many elements in the seventh row have been discovered and named in recent years, highlighting the ongoing exploration and advancement in technology that may lead to the discovery of new elements. The potential for an eighth row, and beyond, exists as we continue to innovate and explore. The number of elements is theoretically limitless, constrained only by our imagination and ingenuity.

It is essential to note that the principal quantum number n must be a whole number, starting from 1 and extending to infinity. This means that while we currently recognize seven shells, the possibility of creating or discovering elements with more than seven shells exists. Thus, the relationship between the rows of the periodic table and the shell numbers of an atom is fundamental, with the understanding that the potential for new discoveries is boundless.

Electronic Structure: Shells Example 1

In atomic structure, the shell number, denoted as \( n \), represents the principal quantum number that indicates the energy level of an electron in an atom. The principal quantum number can take any positive integer value starting from 1 and extending to infinity, corresponding to the rows of the periodic table. Values such as negative integers (e.g., -3, -4) and zero are not valid for \( n \) since they do not represent physical energy levels in an atom. Additionally, non-integer values, such as \( e \) (approximately 2.718), are also not permissible. For example, if \( n = 2 \), this indicates the second shell of an atom, which is a valid and possible value. Therefore, when evaluating potential values for the shell number, only positive integers, starting from 1, are acceptable. In this context, the only viable option presented is \( n = 2 \).

Which of the following shell number values is a possible value for the element highlighted?

• A. n = 10
• B. n = 4
• C. n = 6
• D. n = 7

Answer: (B)

Which electron possesses the lowest possible energy from the image provided?

• A. A
• B. B
• C. C
• D. D
• E. E

Answer: (D)

Here’s what students ask on this topic:

What is the relationship between the shell number (n) and the periodic table rows?

The shell number (n) corresponds directly to the rows or periods of the periodic table. Each row in the periodic table represents a different shell. For example, the first row corresponds to the first shell (n=1), the second row to the second shell (n=2), and so on up to the seventh row, which corresponds to the seventh shell (n=7). As new elements are discovered or created, additional rows and corresponding shells may be added, theoretically extending to infinity.

How does the value of n affect the size and energy level of atomic orbitals?

As the value of n increases, both the size and energy level of atomic orbitals increase. This means that electrons in higher shells (larger n values) are further from the nucleus and possess higher potential energy. For instance, an electron in the second shell (n=2) will have a higher energy level and be located further from the nucleus compared to an electron in the first shell (n=1).

Why is the periodic table considered dynamic in terms of shell numbers?

The periodic table is considered dynamic because it can expand as new elements are discovered or synthesized. Currently, there are seven rows, but future discoveries could lead to the addition of new rows and corresponding shells. This dynamic nature reflects the ongoing advancements in scientific research and technology, allowing for the potential creation of elements with higher shell numbers.

What is the limitation of the shell number (n) in atomic structure?

The limitation of the shell number (n) is that it must be a whole number (integer) starting from 1 and extending to infinity. This means that the smallest possible shell number is 1, and there is no upper limit to the number of shells an atom can theoretically have. The actual number of shells is determined by the number of elements discovered and created, which can increase as scientific exploration progresses.

How are new elements related to the concept of shells in atomic structure?

New elements are related to the concept of shells because each new element can potentially add a new row to the periodic table, corresponding to a new shell. As scientists discover or create new elements, they may occupy higher shells (larger n values), expanding our understanding of atomic structure. This ongoing discovery process highlights the dynamic and evolving nature of the periodic table and atomic theory.