Periodic Table

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Across
  1. 4. the process by which unstable atoms become more stable by emitting particles and radiation
  2. 6. What is the most abundant element that accounts for up to 75 per cent of the observed ordinary matter
  3. 7. Name the neutral atom in the Periodic Table which has the same number of electrons as K+ and Cl-
  4. 8. a colourless, odourless, unreactive gas that forms about 78% of the earth's atmosphere
  5. 10. What is located inside the nucleus, has no charge, and has a mass of one Amu
Down
  1. 1. The group 1 elements
  2. 2. Who is the creator of the periodic table
  3. 3. A solid material which is typically hard,shiny, malleable, fusible, and ductile, with good electrical and thermal conductivity
  4. 5. who discovered the number of protons in the nucleus of each atom
  5. 9. A strong, hard magnetic silvery-grey metal, the chemical element of atomic number 26, much used as a material for construction and manufacturing, especially in the form of steel.