Chemistry crossword

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