Electron configuration

• What is the focus of BTEC Applied Science Unit One Chemistry?

  Electron configuration in atoms
• Where are electrons located in an atom?

  Electrons are in shells around the nucleus
• What are the principal quantum numbers for electron shells?

  n equals one, two, three, etc.
• What are the names of the subshells in electron configuration?

  S, P, D, and F subshells
• How many orbitals does the S subshell have?

  One orbital
• How many orbitals does the P subshell have?

  Three orbitals
• How many orbitals does the D subshell have?

  Five orbitals
• How many electrons can each orbital hold?

  Two electrons
• What is the maximum number of electrons in the first shell?

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

  Eight electrons
• What is the maximum number of electrons in the third shell?

  Eighteen electrons
• What is the electron configuration of fluorine with nine electrons?

  1s2 2s2 2p5
• How do electrons fill orbitals in an atom?

  They fill lower energy orbitals first
• What analogy is used to explain electron filling in orbitals?

  People choose free pairs of seats
• What is the electron configuration of calcium with 20 electrons?

  1s2 2s2 2p6 3s2 3p6 4s2
• How many electrons does a magnesium ion (Mg2+) have?

  Ten electrons
• What is the electron configuration of a magnesium ion (Mg2+)?

  1s2 2s2 2p6
• What should you practice to master electron configurations?

  • Draw electron configuration diagrams for the first 20 elements
  • Draw diagrams for the ions of the first 20 elements
• What happens to the electron configuration of group elements when they form ions?

  • Group 1: +1 charge
  • Group 2: +2 charge
  • Group 7: -1 charge
  • Group 8: No ion formation
• What is the atomic number of calcium?

  20
• What is the electron configuration of neon?

  1s2 2s2 2p6
• What is the significance of the order of filling orbitals?

  • Lower energy orbitals fill first
  • Helps predict electron configurations