electronic configurations

• What do electrons occupy in an atom?

  Shells (energy levels)
• How do electrons fill the shells in an atom?

  Lowest energy levels are filled first
• How many electrons can the first shell hold?

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

  8 electrons
• How many electrons can the third shell hold?

  8 electrons
• What is the electronic configuration of nitrogen?

  • Atomic number of nitrogen: 7
  • Electrons: 7
  • Configuration: 2.5 (2 in first shell, 5 in second)
• What does the periodic table indicate about nitrogen?

  Nitrogen has an atomic number of seven
• How many protons does nitrogen have?

  Seven protons
• If an element has an atomic number of 10, what is its electronic configuration?

  2.8
• How can electronic configurations be represented visually?

  • Draw circles for shells
  • Use crosses to represent electrons
• What is the symbol for hydrogen?

  H
• What is the symbol for helium?

  He
• What is the symbol for lithium?

  Li
• What is the symbol for beryllium?

  Be
• What is the symbol for boron?

  B
• What is the symbol for carbon?

  C
• What is the symbol for nitrogen?

  N
• What is the symbol for oxygen?

  O
• What is the symbol for fluorine?

  F
• What is the symbol for neon?

  Ne