What are Shells, Subshells, and Orbitals? | Chemistry

Najam Academy
19 Jul 202005:59
EducationalLearning
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TLDRThis educational script introduces the fundamental concepts of atomic structure, focusing on shells, sub-shells, and orbitals. It explains that shells, or energy levels, are denoted by 'n' and are categorized into K, L, M, and N shells. Sub-shells, represented by s, p, d, and f, increase in number as shells progress. The script simplifies the concept by associating the number of sub-shells with the shell number. Furthermore, it clarifies that orbitals are regions within sub-shells where the probability of finding electrons is highest, with s sub-shells having one orbital, p having three, and d having five, illustrating the quantum nature of electrons in atoms.

Takeaways
  • 🌀 Shells are energy levels around the nucleus, represented by the principal quantum number 'n'.
  • 🔢 The first shell is denoted as 'n=1' and is also known as the K shell.
  • 📚 Each shell is identified by a letter: K for the first, L for the second, M for the third, and N for the fourth shell.
  • 📈 Subshells are subdivisions within shells, denoted by s, p, d, and f, corresponding to different energy levels.
  • 📊 The number of subshells increases with the shell number: 1 for K, 2 for L, 3 for M, and 4 for N shell.
  • 🧲 The s subshell has one orbital, p has three, d has five, and f has seven orbitals.
  • 📍 Orbitals are regions within subshells where the probability of finding an electron is the highest.
  • 🔑 The notation '3s' means the 's' subshell of the third shell (M shell).
  • 🔍 The notation '4s' refers to the 's' subshell of the fourth shell (N shell).
  • 🌐 Bohr's atomic model describes fixed paths for electrons around the nucleus, which are the shells.
  • 📝 To remember subshells: first shell has one, second has two, third has three, and fourth has four subshells.
Q & A

  • What are shells in Bohr's atomic model?

    -In Bohr's atomic model, shells are fixed paths or energy levels around the nucleus where electrons revolve. They are represented by the principal quantum number 'n'.

  • How are shells denoted in terms of energy levels?

    -Shells are denoted by the principal quantum number 'n', with 'n=1' being the first shell, 'n=2' the second shell, and so on.

  • What are the names of the first four shells according to the script?

    -The first shell is known as the K shell, the second as the L shell, the third as the M shell, and the fourth as the N shell.

  • How many subshells does the K shell have?

    -The K shell has only one subshell, which is the 's' subshell.

  • What are the subshells denoted by?

    -Subshells are denoted by the letters 's', 'p', 'd', and 'f', representing different sub energy levels within a shell.

  • How many subshells does the L shell have and what are they?

    -The L shell has two subshells: the 's' and 'p' subshells.

  • What is the relationship between the shell number and the number of subshells it contains?

    -The number of subshells in a shell corresponds to the shell number. For example, the first shell has one subshell, the second has two, the third has three, and the fourth has four.

  • What does the term 'orbitals' refer to in the context of atomic structure?

    -Orbitals are the regions within subshells where the probability of finding electrons is maximum. They represent the three-dimensional parts where the chances of finding electrons are the highest.

  • How many orbitals does an 's' subshell have?

    -An 's' subshell has one orbital.

  • How many orbitals does a 'p' subshell have?

    -A 'p' subshell has three orbitals.

  • What is the significance of the notation '3s' and '4s' in terms of shells and subshells?

    -The notation '3s' means the 's' subshell of the third shell (M shell), and '4s' means the 's' subshell of the fourth shell (N shell).

Outlines
00:00
🌌 Electron Shells and Subshells in Atomic Structure

This paragraph introduces the concept of electron shells and subshells according to Bohr's atomic model. Shells, also known as energy levels, are represented by the variable 'n' and are categorized by the K, L, M, and N shells corresponding to n=1, 2, 3, and 4, respectively. Each shell is further divided into subshells denoted by s, p, d, and f, with the number of subshells increasing as the shell number increases. The paragraph also explains the mnemonic for remembering the subshells: the first shell has one subshell, the second has two, and so on, with each subsequent shell adding one more subshell type. Additionally, it clarifies the difference between shell notation, such as '3s' indicating the 's' subshell of the third shell (M shell).

05:03
📚 Orbitals and Their Significance in Atomic Theory

The second paragraph delves into the concept of orbitals, which are regions within subshells where the probability of finding electrons is the highest. It emphasizes that orbitals are essentially the three-dimensional spaces where electrons are most likely to be located. The paragraph provides a brief overview of the number of orbitals within each type of subshell: s subshells have one orbital, p subshells have three, and d subshells have five. It concludes by summarizing the information about shells and subshells, mentioning the specific subshells associated with the K, L, M, and N shells, and their corresponding orbitals.

Mindmap
Keywords
💡Shells
Shells, in the context of Bohr's atomic model, refer to the fixed paths or energy levels around the nucleus where electrons revolve. The video script explains that these shells are denoted by the principal quantum number 'n', with the first shell being the K shell (n=1), the second being the L shell (n=2), and so on. Shells are fundamental to understanding atomic structure and electron configuration, as they define the regions where electrons are most likely to be found.
💡Sub-shells
Sub-shells, also known as sub-energy levels, are subdivisions within the main energy shells. They are represented by the letters s, p, d, and f, and determine the shape and orientation of the electron cloud within a shell. The script mentions that the number of sub-shells increases with the shell number: the K shell has one sub-shell (s), the L shell has two (s and p), the M shell has three (s, p, and d), and the N shell has four (s, p, d, and f). Sub-shells play a crucial role in the organization of electrons within an atom.
💡Orbitals
Orbitals are regions within sub-shells where the probability of finding an electron is the highest. They are three-dimensional spaces that describe the most likely locations of electrons around the nucleus. The script clarifies that the s sub-shell has one orbital, the p sub-shell has three, and the d sub-shell has five. Orbitals are essential for understanding the quantum mechanical model of the atom, which supersedes Bohr's model.
💡Principal Quantum Number (n)
The principal quantum number 'n' is an integer that defines the main energy levels or shells in an atom. It is used to describe the average distance of an electron from the nucleus and increases with the energy level. In the script, 'n' is used to differentiate between the first shell (K shell, n=1), the second shell (L shell, n=2), and so forth, up to the fourth shell (N shell, n=4).
💡K Shell
The K shell is the innermost energy level of an atom, denoted by the principal quantum number 'n=1'. It is also known as the first shell and contains only one sub-shell, which is the 1s sub-shell. The script emphasizes that the K shell is the closest to the nucleus and is the most tightly bound, making it the least likely to lose electrons.
💡L Shell
The L shell is the second energy level of an atom, represented by 'n=2'. It is known as the second shell and contains two sub-shells: 2s and 2p. The script illustrates that the L shell is further from the nucleus than the K shell and can accommodate more electrons, contributing to the atom's overall electronic configuration.
💡M Shell
The M shell, with the principal quantum number 'n=3', is the third energy level of an atom. It is also referred to as the third shell and contains three sub-shells: 3s, 3p, and 3d. The script explains that the M shell is even further from the nucleus than the L shell, allowing for more complex electron configurations and a greater variety of chemical properties.
💡N Shell
The N shell is the fourth energy level of an atom, denoted by 'n=4'. It is known as the fourth shell and contains four sub-shells: 4s, 4p, 4d, and 4f. The script indicates that the N shell is the outermost shell discussed in the video, and it can accommodate a larger number of electrons in various sub-shells, influencing the atom's chemical behavior.
💡s Sub-shell
The s sub-shell is a type of sub-shell that can be found in every energy level, starting with the K shell. It is characterized by having a spherical shape and contains only one orbital. The script mentions that the s sub-shell is the first sub-shell in the sequence of sub-shells within a shell, and it is where electrons are most likely to be found close to the nucleus.
💡p Sub-shell
The p sub-shell is another type of sub-shell that exists in energy levels starting from the L shell onwards. It has a dumbbell-shaped electron cloud and contains three orbitals. The script explains that the p sub-shell is the second sub-shell in the sequence and is associated with a higher energy level than the s sub-shell, indicating that electrons in p sub-shells are further from the nucleus.
💡d Sub-shell
The d sub-shell is a sub-shell that starts to appear from the M shell (n=3) onwards. It has a more complex shape than s and p sub-shells and contains five orbitals. The script mentions that the d sub-shell is the third in the sequence of sub-shells and is associated with even higher energy levels, where electrons are less likely to be found close to the nucleus.
💡f Sub-shell
The f sub-shell is the last type of sub-shell discussed in the script, which starts from the N shell (n=4). It is characterized by having seven orbitals and is associated with the highest energy levels within the shells mentioned in the video. The f sub-shell is crucial for understanding the electron configuration of heavier elements and their complex chemical properties.
Highlights

Shells are energy levels in Bohr's atomic model, represented by the variable 'n'.

Each shell has a specific name: K for the first shell, L for the second, M for the third, and N for the fourth.

Shells are numbered with increasing 'n' values, starting from 1 for the first shell.

Subshells are subdivisions within a shell, denoted by s, p, d, and f.

The number of subshells in a shell corresponds to the shell's number: one for K, two for L, three for M, and four for N.

The s subshell has one orbital, p has three, d has five, and f has seven orbitals.

Orbitals are regions within subshells where the probability of finding electrons is maximum.

The K shell (n=1) has only the 1s subshell.

The L shell (n=2) has two subshells: 2s and 2p.

The M shell (n=3) has three subshells: 3s, 3p, and 3d.

The N shell (n=4) has four subshells: 4s, 4p, 4d, and 4f.

The notation '3s' refers to the s subshell of the third shell (M shell).

The notation '4s' refers to the s subshell of the fourth shell (N shell).

Understanding shells, subshells, and orbitals is crucial for grasping atomic structure.

The arrangement of subshells follows a specific pattern that can be easily remembered.

The s subshell is always present in every shell, while p, d, and f subshells appear progressively.

The number of orbitals in a subshell determines the maximum number of electrons it can hold.

The concept of shells, subshells, and orbitals is fundamental to quantum mechanics and chemistry.

This lecture provides a comprehensive overview of the atomic structure related to shells, subshells, and orbitals.

Transcripts

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