Atomic Physics and Space

Atomic Structure

• Atoms are made up of protons, neutrons, and electrons
• Protons have a positive charge, neutrons have no charge, and electrons have a negative charge
• The number of protons determines the element and its atomic number
• The number of protons and neutrons determines the mass number

Nuclear Model of the Atom

• The nucleus is the dense, positively-charged center of the atom
• Electrons orbit the nucleus in shells or energy levels
• The nuclear model was proposed by Rutherford after his famous gold foil experiment

Exam Tips

• Know the basic structure of the atom and the properties of its components
• Understand how the nuclear model was developed and the evidence supporting it
• Be able to calculate atomic number and mass number from given information