Electron structure

• What does the principal quantum number indicate?

  The shell occupied by the electrons
• What is a shell in the context of quantum numbers?

  A group of orbitals with the same principal quantum number
• How many electrons can the 1st shell hold?

  2
• How many electrons can the 2nd shell hold?

  8
• How many electrons can the 3rd shell hold?

  18
• How many electrons can the 4th shell hold?

  32
• What is an orbital?

  A region around the nucleus that can hold up to two electrons with opposite spins
• How many electrons can an orbital hold?

  2

  
• What are the 4 types of orbitals?

  ● s orbital ● p orbital ● d orbital ● f orbital
• What is the shape of an s-orbital?

  Spherical
• What is the shape of a p-orbital?

  Dumb-bell shape
• How many orbitals are found in an s subshell?

  1
• How many electrons can be held in an s subshell?

  2
• How many orbitals does a p subshell have?

  3
• How many electrons can be held in a p subshell?

  6
• How many orbitals are present in a d subshell?

  5
• How many electrons can be held in a d subshell?

  10
• How many orbitals are found in an f subshell?

  7
• How many electrons can fill an f subshell?

  14
• When using ‘electrons in box’ representation, what shape is used to represent the electrons?

  Arrows
• What letter is used to represent the shell number?


  n
• From which shell onwards is the s orbital present?

  n = 1
• From which shell onwards is the p orbital present?

  n = 2
• From which shell onwards is the d orbital present?

  n = 3
• From which shell onwards is the f orbital present?

  n = 4
• What are the rules by which electrons are arranged in a shell?

  • Electrons are added one at a time
  • Lowest available energy level is filled first
  • Each energy level must be filled before the next one can fill
  • Each orbital is filled singly before pairing
  • 4s is filled before 3d

  
• Why does the 4s orbital fill before the 3d orbital?

  4s orbital has a lower energy than 3d before it is filled
• What is the electron configuration of krypton?

  1s22s22p63s23p64s23d104p6

  
• Which electrons are lost when an atom becomes a positive ion?

  Electrons in the highest energy levels