16. The second and third _______________ _______________ can each hold _______________ electrons.
17. The higher _______________ can hold more electrons. 18. The model below represents an atom of _______________.
K U
Knowledge and Understanding 1. Make a table to show the properties of the three sub-atomic particles under the headings:
mass, charge and location.
2. Use the Periodic Table to find out how many protons and electrons there are in an atom of each of the following elements: magnesium, gold, lead, hydrogen and iron.
3. Calcium has an atomic number of 20. Give the arrangement of the electrons in an atom of calcium.
4. Explain how ions form. 5. What are isotopes? 6. Compare the charge and the mass of an electron with the charge and mass of a proton.
T I
Thinking and Investigating 1. Find out about two isotopes of hydrogen. What are their names? How many neutrons do
they each have? Give a property of each isotope.
2. Carbon-14 is an isotope of carbon which is very important in archaeology. Find out what it is used for.
