Electronic Structure: Shells - Online Tutor, Practice Problems & Exam Prep

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

Now recall a shell, which uses the variable n, is a grouping of electrons surrounding the nucleus that ties into their potential energy, so their energy of position. Now we're going to say as the value of n increases, then both the size and energy level of an atomic orbital will increase. And we're going to say here that the energy levels, also the shell numbers of an atom, can be tied to the periods or rows of the periodic table. So, here we have an atom. This atom has its nucleus, and we can see that I have given it 7 shells. Right? Remember, each black orbital represents a shell; 1st shell all the way to the 7th shell here.

We'll realize here that the shells of an atom are directly related to the periods or rows of the periodic table. So, remember, your periods or rows of the periodic table go from left to right. So this is row 1, so this is shell 1, shell 2, 3, 4, 5, 6, and 7. Now currently, there are 7 rows in the periodic table, but what you need to understand about the periodic table is that it is dynamic. A lot of these elements found in the 7th row of the periodic table were discovered within the past decade. A bunch of these here were formally named in the past 10 years. So theoretically, as we move to new planets, as we explore more of Earth, as our technology gets more advanced, we're going to create and find new elements.

So eventually, there's going to be an 8th row of elements, and then a 9th row, and so on and so forth. We're only limited by our imagination and our ingenuity. The number of elements can continuously increase again as we discover them and as we create them. Now we're going to say because of this, the limitation of the n value is that it must be an integer, remember, a whole number, from 1, because the smallest number shell can be is 1, to infinity. There's an infinite number of possible shells. Again, we're only limited by our resources, our imagination, and our ingenuity. We can create new elements with 10 shells, 12 shells, and so on.

So keep in mind the relationship between rows of the periodic table and shell numbers of an atom and realize the limitation of it is that it can be any number from 1 to infinity.

Electronic Structure: Shells Example 1

Which of the following is a possible value for the shell of an atom? So remember, we talked about the only real limitation when it comes to the shell number of an atom is that it's connected to the rows of the periodic table, and because of that, it can be any integer from 1 to infinity. So negative 3 can't be an exact number because that's less than 1. Same thing with negative 4. It has to be a number from 1 to infinity, so 0 is out, and e is out. So n being 2, meaning the second shell of an atom, is a possible value for n. Right? So here the only option that works is option d.

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

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

• A. A
• B. B
• C. C
• D. D
• E. E

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.