Electronic Structure

• What do chemists refer to as principal energy levels?

  Electron shells
• How is the principal quantum number related to the shell's distance from the nucleus?

  The lower the number, the closer to the nucleus
• What is the principal quantum number of the first shell?

  1
• What happens to the energy of a shell as the principal quantum number increases?

  The energy of the shell increases
• How many shells does a chlorine atom have?

  3
• How many shells does potassium have?

  4
• What is the maximum number of electrons each principal quantum shell can hold?

  • n = 1: 2 electrons
  • n = 2: 8 electrons
  • n = 3: 18 electrons
  • n = 4: 32 electrons
• What are the four types of electron subshells?

  s, p, d, f
• How many electrons can each orbital hold?

  2 electrons
• What is the maximum number of electrons in each subshell?

  • s: 2 electrons
  • p: 6 electrons
  • d: 10 electrons
  • f: 14 electrons
• Who developed the currently-accepted model of the atom?

  Niels Bohr
• What concept did Arnold Sommerfeld add to Bohr's model?

  Subshells and orbitals
• How many shells does xenon have?

  5 shells
• What is the total number of electrons in each shell for xenon?

  • Shell 1: 2 electrons
  • Shell 2: 8 electrons
  • Shell 3: 18 electrons
  • Shell 4: 32 electrons
• What does an electron configuration reveal?

  The number and arrangement of electrons
• What is the subshell notation for neon?

  1s$^2$ 2s$^2$ 2p$^6$
• How can electron configurations be shown using box notation?

  • Each box represents an orbital
  • Each half-arrow represents an electron
• What are the blocks of the periodic table?

  s-block, p-block, d-block, f-block
• What do energy level diagrams display?

  The energy level of electrons in orbitals
• Why does the 4s subshell fill before the 3d subshell?

  Because it has a lower energy level
• How many electrons does calcium have?

  20 electrons
• What is the subshell notation for calcium?

  1s$^2$ 2s$^2$ 2p$^6$ 3s$^2$ 3p$^6$ 4s$^2$
• What is spin-pair repulsion?

  Electrons with similar spins repel each other
• How does nitrogen occupy its 2p orbitals?

  Nitrogen occupies empty orbitals first
• How are negatively charged ions formed?

  By adding electrons to the outer subshell
• How are positively charged ions formed?

  By removing electrons from the outer subshell
• What is the electron configuration of a chloride ion (Cl^-)?

  1s$^2$ 2s$^2$ 2p$^6$ 3s$^2$ 3p$^6$
• How do noble gases help in abbreviating electron configurations?

  • They do not readily react
  • Their configurations remain unchanged
  • Used as a reference in shorthand notation
• What is the electron configuration of argon (Ar)?

  1s$^2$ 2s$^2$ 2p$^6$ 3s$^2$ 3p$^6$
• How is potassium's electron configuration abbreviated?

  [Ar] 4s$^1$
• What is unique about transition metals regarding their d subshell?

  They have a partially-filled d subshell
• Which transition metals are mentioned in the material?

  Chromium and copper
• What happens to the 4s electrons when transition metals become ions?

  They are lost before 3d electrons
• How do the outer shell electrons determine chemical properties?

  • Number of outer shell electrons dictates reactivity
  • Elements in s-block lose electrons
  • Elements in p-block gain or share electrons
• Which groups of elements are in the s-block?

  Group 1 and Group 2 metals
• What do elements in the p-block do with electrons?

  They gain or share electrons
• Which elements are examples of p-block elements?

  Nitrogen and oxygen
• Why do elements in Group 0 not gain or lose electrons?

  They have complete subshells