Atomic Theory & Periodic Table

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Across
  1. 2. The force that causes opposite charges (positive and negative) to attract and like charges to repel. These forces hold an atom together.
  2. 6. An element that is usually dull, brittle, and a poor conductor. Found on the right side of ther periodic table.
  3. 8. A horizontal row on the periodic table. Each element in a period having the same number of energy levels.
  4. 10. The scientific idea that all matter is made of tiny particles called atoms.
  5. 11. Atoms of the same element that have the same number of protons but different numbers of neutrons.
  6. 13. A simple representation used to explain or show how something too small, big, or complex works.
  7. 15. The smallest unit of matter that makes up everything around us.
  8. 17. A negatively charged particle that moves around the nucleus of an atom.
  9. 18. A small unit of mass used to measure the weight of subatomic particles and atoms.
  10. 19. A pure substance made of only one kind of atom.
  11. 21. A well-tested explanation that helps us understand why something happens in nature.
  12. 22. The tiny, dense center of an atom that contains protons and neutrons.
Down
  1. 1. The smaller parts inside an atom, called protons, neutrons, and electrons.
  2. 3. A model showing electrons moving quickly in regions around the nucleus instead of in fixed paths.
  3. 4. The mass of an element’s protons and neutrons.
  4. 5. An element with properties of both metals and non-metals. Found on the “staircase” of ther periodic table.
  5. 7. A particle with no charge found inside the nucleus of an atom.
  6. 9. The electrons in the outermost energy level of an atom that are involved in bonding.
  7. 10. The number of protons in an atom’s nucleus, which identifies the element.
  8. 12. A positively charged particle found inside the nucleus of an atom.
  9. 14. The one- or two-letter abbreviation that represents an element on the periodic table.
  10. 16. An element that is usually shiny, a good conductor, and can be shaped or stretched. Found on the left side of ther periodic table.
  11. 20. A vertical column on the periodic table where elements have similar properties.