Memory Anchor:

• Super Challenge:

  Stretch:

  Challenge:

Key Questions:

1. What is the radius of an atom?
   • Atoms are very small, having a radius of about 1 x 10^-10 metres.
2. What is the structure of an atom, with charges for sub-atomic particles?
   • The basic structure of an atom is a positively charged nucleus composed of both protons and neutrons surrounded by negatively charged electrons.
3. How does the radius of an atom compare with the radius of the nucleus of an atom?
   • The radius of a nucleus is less than 1/10,000 of the radius of an atom.
4. Where is most of the mass of an atom concentrated?
   • Most of the mass of an atom is concentrated in the nucleus.
5. How do energy levels differ in terms of distance from the nucleus?
   • The electrons are arranged at different distances from the nucleus (different Energy levels).
6. What might cause the electron arrangements to change (from a lower to higher energy level, for example)?
   • The electron arrangements may change with the absorption of electromagnetic radiation (move further from the nucleus; a higher Energy level) or by the emission of electromagnetic radiation (move closer to the nucleus; a lower Energy level)