1. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 Hodder Education Revision Lessons The fundamental ideas in Chemistry Fundamental ideas in chemistry Click to continue

2. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 Overview Atoms and elements are the building blocks of chemistry. Atoms contain protons, neutrons and electrons. When elements react they produce compounds. Click to continue

3. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 Elements All substances are made of atoms. A substance that is made of only one sort of atom is called an element. There are over 100 different elements. Click to continue

4. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 The periodic table 1 Elements are shown in the periodic table (see the next slide). The groups contain elements with similar properties. What are the properties of: Click to continue the group 1 elements? the group 7 elements?

5. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 The periodic table 2 Click to continue

6. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 Chemical symbols Atoms of each element are represented by a chemical symbol. For example, O represents an atom of oxygen and Na represents an atom of sodium. Click to continue What are the symbols for: carbon magnesium calcium helium

7. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 Atoms 1 Atoms have a small central nucleus, which is made up of protons and neutrons and around which there are electrons. The relative electrical charges are: Click to continue Name of particleCharge Proton+1 Neutron0 Electron–1

8. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 Atoms 2 The number of electrons in an atom is equal to the number of protons in the nucleus. Atoms have no overall electrical charge. Click to continue

9. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 Atomic number and mass number 1 All atoms of a particular element have the same number of protons. Atoms of different elements have different numbers of protons. The number of protons in an atom of an element is its atomic number. The sum of the protons and neutrons in an atom is its mass number. Click to continue

10. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 Click to continue Atomic number and mass number 2 How many protons and neutrons do these elements have? He C O Fe

11. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 Shells and energy levels Electrons occupy particular energy levels. Each electron in an atom is at a particular energy level (in a particular shell). The electrons in an atom occupy the lowest available energy levels (innermost available shells). The shells fill in the order 2, 8, 8... Click to continue

12. AQA GCSE Science & Additional Science Chemistry 1 Topic 1 Electron structure The noble gases are unreactive because their outer shells are full. Draw the electron structures for H, Li, O and Cl.