Atoms & elements/ Periodic table

Task 1. An atom is made special by having its own atomic number and mass number. Define (a) mass number (b) atomic number All chlorine atoms have the same atomic number. However, in chlorine three quarters of the atoms have a mass number of 35, while the others have a mass number of 37. Define relative atomic mass Explain why the relative atomic mass of a chlorine atom is 35.5 The electronic structure of chlorine is 2,8,7. Use the idea of electron shells to explain what this means. Make a table to summaries the properties of the first 20 elements in the periodic table. If you complete this correctly you will meet the criteria for P3.

Task 2. Write a report about your investigation into the chemical properties of elements in group 1 & 7. Include your method, materials used, variables, results & evaluation of the process. See table below for example of results table. If you complete this correctly you will meet the criteria for P4.

Task 3 Write a report about the properties of the elements in groups 1 & 7. 1.       Identify the elements in group 1 & 7, put your results in a table (headings= group 1 elements, group 7 elements). 2.       All Group 1 elements react with oxygen, chlorine and water. Sodium isa typical Group 1 element. Write word equations and chemical equations for reactions of sodium with: a)      oxygen b)      chlorine c)       water 3.       Describe how the reactivity of (a) Group 1 elements and (b) Group 7 elements varies with increasing atomic number. a)      Group 1 elements: b)      Group 7 elements: 4.       Describe the electronic structures of the group 1 elements & what they have in common. 5.       Describe the electronic structures of the group 7 elements & what they have in common. 6.       Explain why the following group 1 & 7 elements are mostly used in the form of compounds: a)      Potassium bromide b)      Sodium chloride If you complete this correctly you will meet the criteria for M3, M4 & D2.