Science: 8. Atoms, Elements and Molecules

Year 7 Science: Atoms, Elements and Molecules (Short Answers)1. What is everything made of?Everything is made of tiny particles called atoms.2. What is an atom?An atom is the smallest part of an element.3. What do particle diagrams show?They show atoms and how they’re arranged in elements or compounds.4. What’s the difference between an element and a compound?Element = only one type of atomCompound = two or more elements joined together5. How do you name elements and find them?Use the Periodic Table. Each element has a name and a symbol, like:Oxygen = OHydrogen = H6. Do compounds have the same properties as the elements they come from?No — compounds usually have different properties.7. What do compound names end in?Often -ide (e.g. magnesium oxide) or -ate (e.g. copper sulfate).8. What is a word equation?It shows what goes in and what comes out in a chemical reaction.Example:hydrogen + oxygen → water9. Can you name some simple compounds?Yes, like:Water (H₂O)Carbon dioxide (CO₂)Salt (sodium chloride)10. What is combustion?Burning something in oxygen.11. What is oxidation?When something joins with oxygen and gets heavier (mass goes up).12. What is decomposition?When a compound breaks down, often using heat — mass goes down.13. What happens to mass in oxidation and decomposition?Oxidation = mass goes upDecomposition = mass goes down14. What are signs of a chemical reaction?Colour changeBubbles (gas)Heat or light15. How do you stay safe in chemical experiments?Wear goggles, tie back hair, and follow teacher instructions.16. Can you recognise compounds by their formula?Yes — learn to match names and formulas like:H₂O = waterCO₂ = carbon dioxide