Chemistry crossword

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Across
  1. 4. group 17 elements in the periodic table;the most reactive non-metals
  2. 8. combination of pure substances;unlike a compound,the components of a mixture do not combine chemically and are not always in the same ratio
  3. 11. variations within a species
  4. 12. the smallest part of an element that is representative of that element;a neutral particle made up of a nucleus containing protons and neutrons,and in which the number of electrons equals the number of protons
  5. 14. invisible negatively charged particle that orbits the nucleus of an atom
  6. 16. atom that has become electrically charged because it has lost or gained electrons;a positive ion is an atom that has lost one or more electrons;a negative ion is an atom that has gained one or more electrons
  7. 17. substance that reacts with another substance or substances in a chemical reaction to create new substances with different properties
  8. 19. pure substance that cannot be broken down into other substances;substance made up of only one type of atom
  9. 21. positively charged particle in the nucleus of an atom
  10. 23. catalyst involved in chemical reactions in living things
  11. 24. ability to do work
Down
  1. 1. horizontal row of elements in the periodic table
  2. 2. positively charged centre of an atom;contains protons and neutrons
  3. 3. substance that helps a chemical reaction to proceed more quickly
  4. 5. amount of mass in a given volume of a substance
  5. 6. element that has both metallic and non-metallic properties
  6. 7. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy
  7. 8. shiny,malleable,ductile element that conducts electricity
  8. 9. description of a substance that can be pounded or rolled into sheets
  9. 10. new substances produced in a chemical reaction between reactants
  10. 13. group of atoms joined by covalent bonds
  11. 15. chemical combination of two or more elements in a specific ratio
  12. 18. neutral particle in a nucleus of an atom
  13. 20. organic molecules made up of atoms of carbon,hydrogen and oxygen (ex,fats,oils and waxes);lipids are insoluble in water
  14. 22. vertical column of elements in the periodic table;elements in a family all have similar chemical properties;also called a group