Yr 9 It's Elementary

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Across
  1. 5. Particles of different elements that are chemically combined
  2. 6. Unstable atoms that undergo nuclear decay
  3. 9. This substance has the chemical formula H₂O
  4. 10. Electrons are arranged in what around the nucleus of an atom
  5. 13. The variable that is measured in an experiment
  6. 14. A subatomic particle found in the nucleus of an atom, has no charge
  7. 15. A decay particle that is a cluster of 2 protons & 2 neutrons
  8. 16. A change in the physical properties of a substance without changing its chemical compoisition is called a what change
  9. 17. A subatomic particle found somewhere around the outside of an atom, has a negative charge
  10. 20. Refers to using the correct equipment during an experiment and taking correct measurements
  11. 21. An atom that is not radioactive and is bound together is called a what atom
  12. 23. An element with the symbol O
  13. 25. Particles of one type, the atoms inside them are all the same
  14. 27. The number of protons in an element is called the what number
Down
  1. 1. A subatomic particle found in the nucleus of an atom, has a positive charge
  2. 2. The smallest particle of matter that cannot be divided by chemical or physical means
  3. 3. Alpha radiation is unable to what through human skin
  4. 4. The emission of electromagnetic radiation or particles from an atom is known as
  5. 6. Refers to conducting an experiment repeatedly with a small range of results
  6. 7. The variable that gets changed in an experiment
  7. 8. Atoms with the same number of protons but a different number of neutrons are called this
  8. 11. A change in a substance that results in a new substance being formed is called a what change
  9. 12. A decay particle that converts a neutron into a proton, as well as emitting an electron
  10. 18. The variables that are kept the same in an experiment
  11. 19. The time in which 50% of the radioactive atoms in a sample of radioisotope are expected to decay
  12. 22. Gamma radiation and ________ are highly penetrating electromagnetic radiation.
  13. 24. A type of decay when the protons and neutrons simply rearrange inside the nucleus, and form of electromagnetic wave is emitted
  14. 25. Beta Radiation is a light, short-range particle and is actually an _________ electron
  15. 26. A substance made up of more than one type of element or compound
  16. 28. The number of protons + neutrons in an element = what number