Electron Configuration

• What is the purpose of learning about electronic arrangement?


  To deduce the electronic configuration in terms of ‘s’, ‘p’, and ‘d’ orbitals.
• What does the mass number of an element represent?


  The sum of its protons and neutrons.
• What does the atomic number tell us?


  The number of protons in an element.
• How does the number of outer electrons relate to an element's period?


  It indicates in which period the element is located.
• What is the symbol for Chromium?


  Cr
• How can the periodic table help us with elements?


  It can help predict an element’s reactivity.
• What are the key terms related to electronic arrangement?

  • Principal quantum number, n
  • Aufbau principle
  • Hund’s rule
  • Pauli exclusion principle
  • Orbital
  • Energy level
• What does the term "shell" refer to in atomic structure?


  A particular energy level.
• How is the shell in which an electron is found described?

  By the principal quantum number, n.
• What is the modern understanding of where electrons are found?

  Electrons occupy areas of 3D space called orbitals.
• What are orbitals in atomic structure?


  Volumes of space around the nucleus where there is a high chance of finding an electron.
• How many different types of orbitals are there?


  Four: s, p, d, and f.
• What is the maximum number of electrons that an orbital can hold?


  Two electrons with opposite spins.
• What shape do s orbitals have?


  Spherical shape.
• What shape do p orbitals have?


  Hourglass shape.
• How are p orbitals oriented in space?


  They can lie along the x, y, or z axis.
• What shape do d orbitals have?


  Cloverleaf shape.
• How many d orbitals are there at the third energy level?


  Five d orbitals.
• What is the characteristic of f orbitals?


  They have more complex shapes.
• How many f orbitals are there at the fourth and higher levels?


  Seven f orbitals.
• What are the four sub-levels in order of increasing energy?


  1. s
  2. p
  3. d
  4. f
• What is the maximum number of electrons each sub-level can hold?


  • f: 14 electrons
  • d: 10 electrons
  • p: 6 electrons
  • s: 2 electrons
• What does the Aufbau principle state?


  Lowest energy sub-levels are occupied first.
• Which sub-level fills first according to the Aufbau principle?


  The 1s sub-level.
• What is the relationship between the 4s and 3d sub-levels?


  The 4s sub-level is lower in energy than the 3d sub-level.
• What is the spin property of electrons?


  Electrons have two states: 'up' and 'down'.
• What does the Pauli exclusion principle state?


  Each orbital may contain no more than two electrons.
• What does a spin diagram represent?


  How the orbitals are filled with electrons.
• What does Hund’s rule state?


  Single electrons occupy all empty orbitals before pairing up.
• What are the rules for writing electronic configurations?

  1. Fill the orbitals in order of increasing energy.
  2. When there are more than one orbital of the same energy, occupy them singly first.
  3. Each orbital can hold a maximum of two electrons.
• What is the task related to electronic configurations for the first 36 elements?


  Use s, p, d, f notation to write electron configurations.
• What is the electronic configuration for Hydrogen (H)?


  1s$^1$
• What is the electronic configuration for Helium (He)?


  1s$^2$
• What is the electronic configuration for Lithium (Li)?


  1s$^2$ 2s$^1$
• What is the electronic configuration for Beryllium (Be)?


  1s$^2$ 2s$^2$
• What is the electronic configuration for Boron (B)?


  1s$^2$ 2s$^2$ 2p$^1$
• What is the electronic configuration for Carbon (C)?


  1s$^2$ 2s$^2$ 2p$^2$
• What is the electronic configuration for Nitrogen (N)?


  1s$^2$ 2s$^2$ 2p$^3$
• What is the electronic configuration for Oxygen (O)?


  1s$^2$ 2s$^2$ 2p$^4$
• What is the electronic configuration for Fluorine (F)?


  1s$^2$ 2s$^2$ 2p$^5$