Atomic structure & electron configuration

• What does the term "periodicity" refer to in the context of the periodic table?


  It refers to the recurring trends in the properties of elements
• How is periodicity linked to the modern periodic table?


  Periodicity is reflected in the arrangement of elements in rows and columns based on their properties
• What does Bohr's diagram illustrate regarding sub-atomic particles?


  It shows the arrangement of protons, neutrons, and electrons in an atom
• What are sub-shells in atomic structure?


  Sub-shells are divisions of electron shells that contain orbitals
• How are electrons arranged within sub-shells?

  Electrons are arranged in orbitals within sub-shells according to specific rules
• What is the maximum number of electrons in the first shell?


  2 electrons
• What is the maximum number of electrons in the second shell?


  8 electrons
• What is the mass of a proton?


  1 atomic mass unit (amu)
• What is the charge of a neutron?


  Neutral charge
• What is the mass of an electron?


  1/1840 amu
• Why do elements have no overall electrical charge?


  Because they have equal numbers of protons and electrons
• What is the significance of Mendeleev's periodic table?


  Mendeleev arranged elements by increasing atomic mass and left gaps for undiscovered elements
• Why did other scientists accept Mendeleev's periodic table?


  Because it successfully predicted the properties of undiscovered elements
• What is the atomic number of copper?


  29
• What is the atomic number of lithium?


  3
• What is the atomic number of manganese?


  25
• What is the Aufbau principle?


  It states that electrons fill orbitals starting from the lowest energy level to the highest
• How do electrons spin in orbitals?


  Electrons spin in two different directions: clockwise and anti-clockwise
• What happens when all orbitals are occupied with one electron?


  The remaining electrons will pair up in the opposing spin
• What is the electron configuration of oxygen?


  1s² 2s² 2p⁴
• What is the electron configuration of scandium?


  1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹ 4s²