9. Electrons in Atoms and the Periodic Table

Electronic Structure: Shells

9. Electrons in Atoms and the Periodic Table

Electronic Structure: Shells: Videos & Practice Problems

Topic summary

In atomic theory, the principal quantum number (n) indicates the energy level and size of an atomic orbital, with values ranging from 1 to infinity. Each period in the periodic table corresponds to a shell, with currently seven known rows. As technology advances, new elements may be discovered, potentially leading to additional rows. Understanding the relationship between shell numbers and periodic table rows is crucial for grasping atomic structure and the dynamic nature of elements.

Shell number gives both the size and energy of the shell.

Electronic Structure:Shells

concept

Electronic Structure: Shells Concept 1

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Electronic Structure: Shells Concept 1 Video Summary

In atomic structure, the concept of shells, denoted by the variable n, represents the grouping of electrons surrounding the nucleus. 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 an atomic orbital also increase. This relationship is directly tied to the periods or rows of the periodic table, where each period corresponds to a specific shell of an atom.

For instance, an atom with seven shells aligns with the seven rows currently present in the periodic table. Each shell corresponds to a period, starting from shell 1 for the first row, progressing through to shell 7 for the seventh row. It is important to note that the periodic table is dynamic; many elements in the seventh row have been discovered or named in recent years. As scientific exploration advances, particularly with new technologies and discoveries on Earth and beyond, the potential for new elements to be created or found is vast. This could lead to the eventual addition of an eighth row, ninth row, and so forth.

The integer value of n must always be a whole number, starting from 1 and theoretically extending to infinity. This means that there is no upper limit to the number of shells an atom can possess, as we are only constrained by our resources and creativity. Thus, the relationship between the rows of the periodic table and the shell numbers of an atom is fundamental, with the understanding that the possible values for n can range from 1 to infinity.

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Electronic Structure: Shells Example 1

Video duration:

38s

Electronic Structure: Shells Example 1 Video Summary

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 or zero are not valid for \( n \) because they do not correspond to any physical energy level in an atom. For instance, \( n = 2 \) signifies the second shell, which is a legitimate and possible value for the shell of an atom. Therefore, when evaluating potential values for \( n \), only positive integers, such as 1, 2, 3, and so forth, are acceptable. In summary, the only valid option for the shell number of an atom from the given choices is \( n = 2 \), which corresponds to the second energy level or shell.

Problem

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

n = 10

n = 4

n = 6

n = 7

Problem

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

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Here’s what students ask on this topic:

What is the principal quantum number (n) and how does it relate to the energy levels of an atom?

The principal quantum number (n) is a fundamental concept in atomic theory that indicates the energy level and size of an atomic orbital. It is denoted by the variable n and can take on integer values starting from 1 and extending to infinity. As the value of n increases, both the size and energy level of the atomic orbital increase. This means that electrons in higher energy levels (higher n values) are further from the nucleus and possess more potential energy. The principal quantum number also correlates with the periods or rows of the periodic table, where each period corresponds to a specific shell number. For example, elements in the first period have electrons in the n=1 shell, while elements in the second period have electrons in the n=2 shell.

How are the shells of an atom related to the periods of the periodic table?

The shells of an atom are directly related to the periods (rows) of the periodic table. Each period corresponds to a specific shell number, denoted by the principal quantum number (n). For instance, the first period corresponds to the n=1 shell, the second period to the n=2 shell, and so on. Currently, there are seven known periods in the periodic table, which means there are seven known shells. As new elements are discovered or created, additional periods (and thus additional shells) may be added. This relationship helps in understanding the arrangement of electrons around the nucleus and the overall structure of the atom.

Can the number of shells in an atom be infinite?

Yes, theoretically, the number of shells in an atom can be infinite. The principal quantum number (n) can take on any integer value from 1 to infinity. This means that as new elements are discovered or created, additional shells can be added. Currently, we know of elements with up to seven shells, corresponding to the seven periods of the periodic table. However, as technology advances and new elements are found or synthesized, it is possible to have elements with more than seven shells. The only limitation is our current resources, imagination, and ingenuity.

Why is the periodic table considered dynamic?

The periodic table is considered dynamic because it evolves as new elements are discovered or synthesized. Over the past decade, several elements in the seventh period have been formally named and added to the table. As scientific research progresses and technology advances, it is likely that more elements will be discovered, leading to the addition of new periods and shells. This dynamic nature reflects the ongoing exploration and understanding of atomic structure and the potential for discovering new elements beyond the current known ones.

What is the significance of the relationship between shell numbers and periodic table rows?

The relationship between shell numbers and periodic table rows is significant because it helps in understanding the arrangement of electrons in an atom. Each row (period) of the periodic table corresponds to a specific shell number, denoted by the principal quantum number (n). For example, elements in the first row have electrons in the n=1 shell, while elements in the second row have electrons in the n=2 shell. This relationship provides a systematic way to determine the electron configuration of elements and predict their chemical properties. It also highlights the periodic nature of elements, where elements in the same column (group) have similar valence electron configurations and exhibit similar chemical behavior.

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