1. Aim: What makes the atoms of one element different to the atoms of another element?

2. As much as we would like to, we cannot turn lead into gold, but why can we not? Why are atoms of lead different to those of gold and why can we not just simply change them?

3. To answer this we first of all have to think about what an atom is. Much research was carried out into this and in 1909 a famous scientist Ernest Rutherford first identified the atom as we see it today.

4. He took a very thin bit of gold foil surrounded in photographic paper and fired radioactive particles at it. The photographic paper would change colour when hit by radioactive particles.

5. His results showed that most of the gold foil is space as the radioactive particles went straight through the foil. This left little cirles where the gold atoms were. It was not until 1932 that we finally established the structure of the atom. Lets look at an atoms of helium.

6. Activity 5 Atoms contain three different particles Electrons are negatively charged particles that orbit a mass at the centre of the atom. The centre of the atom is known as the nucleus. This contains positive proton particles and neutral neutron particles. Use this info to label activity 5.

7. Activity 5

8. This atomic structure is unique to helium. Every element has its own atomic structure.

9. The number of protons is equal to the atomic number of an element so helium has the atomic number 2. You should also notice that in an atom the number of positive protons is equal to the number negative electrons. This ensures the charges are balanced within the atom.

10. An atom of helium has a mass of 4 atomic mass units. This is made up from the protons plus the number neutrons. Every proton and neutron has a mass of 1 atomic mass unit (amu) Electrons are so small we do not count their mass.

11. Atomic mass units (amu) are special units we use to measure the mass of particles on an atomic scale. Use the information in the book to complete the table ParticleChargeRelative Atomic Mass (amu) Location in the Atom Positive 0Orbits nucleus 1Nucleus

12. Activity 7a – Making an atom In your group you will be given a supply of string and some beads. Using this equipment you have to show the structure of an atom of a given element.

13. Activity 7b – Making an atom Using the instruction card, complete activity 7 to make an atom

14. Once everyone is finished go round and have a look at the atoms. Copy and complete the following table: ElementHow I Identified the Element

15. The Periodic Table can tell us a lot of information. The atomic number tells us the number of protons and therefore the number of electrons as they have to be equal in atoms. We can also use the data book to find the relative atomic mass of an element.

16. We have a special notation for this information; here is this information for helium; Copy this into your notes

17. Using your data book give information on lithium’s atomic number and mass like the example of helium on the previous page.

18. Activity 8 Copy and use your data book to complete the table below; Stuck? Ask your teacher for the help sheet Element Name Atomic Number Number Protons Number Electrons Number Neutrons Mass (amu) 1 6 16 19 10

19. How are the atoms of the same element similar? The atom has two main parts, the nucleus and the electrons, explain why the nucleus has a positive charge. Why does an atom not have an overall charge?

20. How are the atoms of the same element similar? Atoms of the same element contain the same number of protons and electrons

21. The atom has two main parts, the nucleus and the electrons, explain why the nucleus has a positive charge. The nucleus has a positive charge as it contains positive protons and neutral neutrons leaving it neutral overall

22. Why does an atom not have an overall charge? The number of positive protons in an atom are equal to the number of negative electrons leaving the atom with no overall charge Homework 1