Unit 1 Vocabulary

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Across
  1. 2. The tiny, very dense, positively charged region in the center of an atom that is made up of protons and neutrons
  2. 4. The smallest particle of an element; made of electrons, protons, and neutrons
  3. 5. A pure substance composed of the same type of atom throughout
  4. 6. The rows in a periodic table that classify the elements by the number of electron shells
  5. 7. Elements that have properties of both metals and nonmetals
Down
  1. 1. A conceptual model of the atom in which a small, positively charged nucleus is surrounded by planetary electrons
  2. 2. Nonreactive nonmetals in Group 18 of the periodic table
  3. 3. The columns on a periodic table that arrange the elements by the number of electrons that are in the outermost shell