atomic structure

• What particles are found in the nucleus of an atom?

  Protons and neutrons
• What charge do protons carry?

  Positive charge
• What is the charge of an electron?

  Negative charge
• How do electrons move in an atom?

  In orbits or shells around the nucleus
• Why are atoms considered neutral?

  They have equal numbers of protons and electrons
• What is the relative mass of a proton?

  1
• What is the relative mass of an electron?

  Tiny, approximately 1/2000
• What does the atomic number represent?

  The number of protons in an atom
• Who proposed the plum pudding model of the atom?

  JJ Thomson
• What does the plum pudding model suggest about atoms?

  Atoms are made of smaller particles
• What experiment did Rutherford conduct to discover the nucleus?

  Fired alpha particles at gold foil
• What did Rutherford's experiment reveal about the atom?

  Most of the atom is empty space
• Who discovered the neutron?

  James Chadwick
• What is the mass of the nucleus compared to the atom?

  Most of the mass is in the nucleus
• What are the key changes to atomic structure models over time?

  • 1897: Electron discovered (Thomson)
  • 1911: Nucleus discovered (Rutherford)
  • 1913: Shells discovered (Bohr)
  • 1932: Neutrons discovered (Chadwick)
• What is the maximum number of electrons in shell 1?

  2 electrons
• What is the maximum number of electrons in shell 2?

  8 electrons
• What is the maximum number of electrons in shell 3?

  8 electrons
• What is the maximum number of electrons in shell 4?

  2 electrons
• How do electrons fill the shells in an atom?

  • Fill closest shells first
  • Shell 1: max 2 electrons
  • Shell 2: max 8 electrons
  • Shell 3: max 8 electrons
  • Shell 4: max 2 electrons
• What is the electron configuration for sodium (Na)?

  2, 8, 1
• What is the electron configuration for magnesium (Mg)?

  2, 8, 2
• What is the electron configuration for carbon (C)?

  2, 4
• What is the electron configuration for oxygen (O)?

  2, 6
• What is the electron configuration for fluorine (F)?

  2, 7
• What is the electron configuration for neon (Ne)?

  2, 8
• What is the electron configuration for lithium (Li)?

  2, 1
• What is the electron configuration for beryllium (Be)?

  2, 2
• What is the electron configuration for boron (B)?

  2, 3
• What is the electron configuration for nitrogen (N)?

  2, 5
• What is the electron configuration for phosphorus (P)?

  2, 8, 5
• What is the electron configuration for sulfur (S)?

  2, 8, 6
• What is the electron configuration for chlorine (Cl)?

  2, 8, 7
• What is the electron configuration for argon (Ar)?

  2, 8, 8
• What is the electron configuration for potassium (K)?

  2, 8, 8, 1
• What is the electron configuration for calcium (Ca)?

  2, 8, 8, 2
• What do group and period numbers indicate in the periodic table?

  • Group number: number of electrons in outer shell
  • Period number: number of shells containing electrons