electron structure

• What is the maximum number of electrons that can fill the first shell?

  2
• Define the term "orbital".

  An orbital is a region within an atom that can hold up to two electrons, with opposite spins.
• What is the difference between a shell, sub-shell, and orbital?

  A shell is a main energy level, a sub-shell is a group of the same type of atomic orbitals, and an orbital is a region where electrons are likely to be found.
• Describe the shapes of s- and p- orbitals.

  s orbitals are spherical, while p orbitals are dumbbell-shaped.
• How many orbitals are in the s-, p-, and d-subshells?

  s has 1 orbital, p has 3 orbitals, and d has 5 orbitals.
• What is the order of filling orbitals according to the Aufbau principle?

  Electrons fill low energy orbitals before higher energy ones.
• Why is electron pairing relevant in orbitals?

  Electron pairing reduces mutual repulsion between electrons in the same orbital.
• Write the electron configuration for sodium.

  2,8,1
• Where are electrons found in an atom?

  Electrons are found in energy levels or shells around the nucleus.
• How many electrons are in a calcium atom?

  20
• How many electrons are in a chlorine atom?

  17
• What is the electronic configuration of oxygen?

  2,6
• What is the electronic configuration of magnesium?

  2,8,2
• What is the electronic configuration of potassium?

  2,8,8,1
• How many energy levels are occupied in sulfur?

  3
• How many outer shell electrons are there in carbon?

  4
• What does the principal quantum number (n) indicate?

  The principal quantum number indicates the shell that the electrons occupy, with 1 being closest to the nucleus.
• How many electrons can fit into the 2p sub-shell?

  6
• How many electrons can fit into the 3rd shell?

  18
• What is the maximum number of electrons that can fit into a 1s orbital?

  2
• How many electrons can fit into a 4p sub-shell?

  6
• How many electrons can fit into a 4d orbital?

  2
• What is the significance of the Aufbau principle in electron configuration?

  The Aufbau principle states that electrons fill the lowest energy orbitals first before moving to higher energy orbitals.
• What is Hund's rule regarding electron filling in orbitals?

  Hund's rule states that electrons fill degenerate orbitals singly before pairing up.
• How does the energy level of sub-shells change within a shell?

  Each new type of sub-shell added has a higher energy level than the previous one.
• What is the shape of s orbitals?

  s orbitals are spherical in shape.
• What is the shape of p orbitals?

  p orbitals are dumbbell-shaped.
• How many f orbitals are present in a shell from n=4 upwards?

  7
• What is the maximum number of electrons that can fit into f orbitals?

  14
• How does the filling order of orbitals differ from the expected order based on energy levels?

  4s fills before 3d because 4s is of lower energy than 3d.
• What does the direction of the arrow in sub-shell notation indicate?

  The direction of the arrow indicates the spin of the electron.
• How do you represent electrons in orbitals using the "electrons in boxes" method?

  You draw boxes for each orbital and use arrows to represent electrons with opposite spins.
• What is the electronic configuration of fluorine?

  1s² 2s² 2p⁵
• What is the electronic configuration of aluminum?

  1s² 2s² 2p⁶ 3s² 3p¹
• What is the electronic configuration of phosphorus?

  1s² 2s² 2p⁶ 3s² 3p³
• What is the electronic configuration of nitrogen?

  1s² 2s² 2p³
• What is the electronic configuration of neon?

  1s² 2s² 2p⁶
• What is the electronic configuration of magnesium?

  1s² 2s² 2p⁶ 3s²
• What is the electronic configuration of sulfur?

  1s² 2s² 2p⁶ 3s² 3p⁴
• What is the electronic configuration of iron?

  1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶ 4s²