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Part B: atomic number
Find out the answers to the following by searching the ‘net or by using your prior knowledge.
1. List the symbols for the elements carbon, oxygen and hydrogen.
2. Find out how many protons there are inside the nuclei of carbon, oxygen and hydrogen. You may find this on a copy of a Periodic table.
The number of protons inside an atom tells us what type of atom it is. For example, every atom that has 2 protons in its nucleus is Helium; every atom that has 7 protons in its nucleus is Nitrogen.
3. Find out what the term ‘atomic number’ refers to.
The teacher will show you where the atomic mass is written next to a symbol. If you are working independently, check the link below for some hints.
Go to the following link and use it to answer question 7 below:
http://www.media.pearson.com.au/schools/cw/au_sch_rickard_sd2_1/int/atom-x.html
4. List the elements with atomic mass 4, 10, 15 and 20.
5. Use the Internet to find the atomic numbers of Lead (Pb), Gold (Au) and Uranium (U).
We will share the answers to questions 7 and 8 in a class discussion.
Part C: Mass number
The heaviest part of an atom is its nucleus, that is, the protons and neutrons of the nucleus make up the greatest portion of the mass of the atom.
6. Using this information as a hint, what do you think that the ‘mass number’ of an atom refers to?
7. The mass number of one type of Hydrogen is 2. Given that Hydrogen is the first element on the Periodic table, how many protons and neutrons are there in an atom of this type of Hydrogen?
8. Using the Atom-X program (the hyperlink above), find out how many different types of Hydrogen there are.
9. How is the mass number of a substance written? Give an example.
10. Using Atom-X, make a list of the different mass numbers possible for Carbon.
Part D: Extension work
11. Many forms of many elements are radioactive. Find out what this means.
12. As you create atoms in Atom-X you will be told when the atoms are ‘most happy’. With what charge is Hydrogen ‘most happy’?
13. Where, in terms of the symbol for an element, is the charge of an atom written? Give an example of how to write this information.
14. Imagine a neutral atom of Nitrogen. How many protons and electrons will it have?
15. Using Atom-X, create the most stable form of Nitrogen with the appropriate charge.
An ion is an atom that has an overall charge, that is, it is not neutral.
16. What is the charge on Nitrogen that makes it ‘most happy’ (most stable)?
17. From the first 20 elements, make a list of the elements which are ‘happiest’ (most stable) as neutral atoms.
18. Make a list of three elements that form negative ions and three that form positive ions.
Part E: Wrap –up / check your understanding
19. The atomic number for every atom of an element is the same. For example, all carbon atoms have 6 protons. Do all carbon atoms have the same mass number? Explain your answer.