Across
- 2. The combination of elements to form compounds has a chemical formula and a
- 6. The formula identifies which elements and how many of each are in the compound.
- 8. Is also a cloudy mixture, but the particles are sosmall that they cannot be filtered out easily (emulsionsare types of colloids in which liquids are dispersed inliquids)
- 9. The only elements in this group known to produce a magnetic field are iron, cobalt and nickel
- 10. Occurs when two or more substances react and create one or more new substances
- 17. Each substance is not clearly visible(A substance dissolved in water is called an aqueous solution)
- 19. In a chemical reaction, the total mass of the reactants,is always equal to the total mass of the products.
- 21. Are reactive nonmetallic elements that form strongly acidic compounds with hydrogen, from which simple salts can be made
- 23. Early chemists used symbols of the sun and the planets to identify the elements known to them.this later was a problem, when more elements were discovered, because they ran out of planets.
- 25. Are not consumed in the reaction. These can be found in living and non-living things.
Down
- 1. Are pure substances formed as a result of the attraction between particles of opposite charges, called ions.
- 3. The substances at the beginning of the reaction are called
- 4. In between elements were called having properties of both metals and non-metals.
- 5. The new materials produced by the reaction are called
- 7. Each substance in the mixture is visible
- 11. Part pharmacist and part mystic) developed many useful procedures, including distillation, and they described the properties of many different materials. They also thought they could change lead and copper into gold
- 12. Cannot be broken down into any simpler substance
- 13. Is a combination of two or more elements in fixed proportions
- 14. Change in color Change in odour, Formation of a gas (bubbles) in a liquid, Formation of a solid (precipitate) in a liquid, Release or absorption of energy (heat), The change is difficult to reverse,
- 15. Is a slow chemical change that occurs when oxygen in the air reacts with a metal
- 16. compounds When non-metals combine, they producea pure substance called a
- 18. Charges A superscript ( + ) or a ( – ) are used to indicate the charge. Na+ and Cl
- 20. Are very reactive, electropositive, monovalent metals forming strongly alkaline hydroxides.
- 22. Is a cloudy mixture in which tiny particles are held(suspended) with another substance, and can be filtered out
- 24. Help in the reactions in the body, which break down food. They also get rid of poison in the body.