Electron Energy Levels

• What does the atomic number of an element indicate?

  The atomic number indicates the number of protons in the nucleus
• How many protons are in the nucleus of a helium atom?

  Two protons
• How many electrons does a neutral helium atom have?

  Two electrons
• What are energy levels in an atom also known as?

  Electron shells
• What is the maximum number of electrons the first energy level can hold?

  Two electrons
• What is the maximum number of electrons the second energy level can hold?

  Eight electrons
• What is the maximum number of electrons the third energy level can hold?

  Eight electrons
• How do you assign electrons into energy levels for hydrogen?

  Hydrogen has one electron in the first energy level
• How can you represent the number of electrons in an atom using brackets?

  By writing the number of electrons in brackets
• How many electrons does lithium have and how are they distributed in energy levels?

  Lithium has three electrons: two in the first level and one in the second level
• What does the number of electrons in the outer energy level indicate?

  It indicates the group number of that element in the periodic table
• In which group is lithium found in the periodic table?

  Group one
• How many electrons does boron have in its outer energy level?

  Three electrons
• In which group is boron found in the periodic table?

  Group three
• How many electrons does carbon have in total and in its outer energy level?

  Carbon has six electrons total: two in the first level and four in the outer level
• In which group is carbon found in the periodic table?

  Group four
• How many electrons does neon have in its outer energy level?

  Eight electrons
• What is significant about elements with a full outer energy level?

  They are found in group zero of the periodic table
• What are the two elements mentioned that have a full outer energy level?

  Helium and neon
• How many electrons does sodium have in total and how are they distributed in energy levels?

  Sodium has 11 electrons: two in the first level, eight in the second level, and one in the third level
• In which group is sodium found in the periodic table?

  Group one
• What is the process for determining the electronic structure of the first 20 elements in the periodic table?

  1. Identify the atomic number.
  2. Determine the number of protons and electrons.
  3. Assign electrons to energy levels:

  • First level: max 2 electrons
  • Second level: max 8 electrons
  • Third level: max 8 electrons

  1. Count the electrons in the outer energy level to find the group number.
• What are the key facts about the first three elements in the periodic table regarding their electron configuration?

  • Hydrogen: 1 electron (1st level)
  • Helium: 2 electrons (1st level)
  • Lithium: 2 electrons (1st level), 1 electron (2nd level)
• What are the electron configurations for the elements boron, carbon, and neon?

  • Boron: 2 electrons (1st level), 3 electrons (2nd level)
  • Carbon: 2 electrons (1st level), 4 electrons (2nd level)
  • Neon: 2 electrons (1st level), 8 electrons (2nd level)
• What are the characteristics of noble gases in the periodic table?

  • Full outer energy level
  • Found in group zero
  • Includes helium and neon