Electron Energy Levels

• What should you be able to do by the end of the video?

  Represent the electronic structure of elements and determine the group number of an element in the periodic table.
• What is the significance of the atomic number in an atom?

  • Indicates the number of protons in the nucleus
  • Determines the number of electrons in a neutral atom
• How many protons are in the nucleus of a helium atom?

  Two protons.
• Why does a helium atom have two electrons?

  Because it has the same number of electrons as protons.
• What are electron energy levels also known as?

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

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

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

  Eight electrons.
• How do you assign electrons into energy levels?

  • Fill the first energy level to its maximum
  • Move to the next energy level and continue filling
• How many electrons does a hydrogen atom have?

  One electron.
• How is the electron configuration of helium represented?

  By writing a two in brackets for its two electrons in the first energy level.
• How many electrons does a lithium atom have?

  Three electrons.
• What does the number of electrons in the outer energy level indicate?

  • It tells us the group number of that element in the periodic table.
• What group is lithium in?

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

  Three electrons.
• What group is boron in?

  Group three.
• How many electrons does carbon have in total?

  Six electrons.
• How many electrons does carbon have in its outer energy level?

  Four electrons.
• What group is carbon in?

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

  Eight electrons.
• What characterizes elements in group zero of the periodic table?

  • They have a full outer energy level.
  • Includes noble gases like helium and neon.
• How many electrons does sodium have?

  Eleven electrons.
• How are the electrons distributed in sodium's energy levels?

  Two in the first, eight in the second, and one in the third energy level.
• What group is sodium in?

  Group one.