Across
- 3. a substance with constant composition that can be broken down into elements by chemical processes
- 4. a positively charged particle in an atomic nucleus
- 5. the total number of protons and neutrons in the atomic nucleus of an atom
- 10. the change of substances into other substances through a reorganization of the atoms; a chemical reaction.
- 13. the material of the universe
- 14. a negatively charged particle that occupies the space around the nucleus of an atom
- 15. atoms of the same element (the same number of protons) that have different numbers of neutrons. They have identical atomic numbers but different mass numbers.
- 16. a change in the form of a substance, but not in its chemical nature; chemical bonds are not broken in a physical change.
- 19. the observation that atoms of nonmetals form the most stable molecules when they are surrounded by eight electrons (to fill their valence orbitals)
- 20. the tendency of an atom in a molecule to attract shared electrons to itself
- 21. elements that have both metallic and non-metallic properties.
- 23. the force that holds two atoms together in a compound
- 24. an element that does not exhibit metallic characteristics. Chemically, a typical nonmetal accepts electrons from a metal.
- 25. the electrons in the outermost occupied principal quantum level of an atom
Down
- 1. the number of protons in the nucleus of an atom; each element has a unique atomic number
- 2. a vertical column of elements having the same valence electron configuration and similar chemical properties.
- 6. the small, dense center of positive charge in an atom
- 7. a chart showing all the elements arranged in columns in such a way that all the elements in a given column exhibit similar chemical properties
- 8. neutral particle contained in the nucleus of the particle, slightly more massive than a proton but has no charge.
- 9. the science that deals with the materials of the universe and the changes that these materials undergo.
- 11. an atom or a group of atoms that has a net positive or negative charge.
- 12. the fundamental unit of which elements are composed
- 13. an element that gives up electrons relatively easily and is typically lustrous, malleable, and a good conductor of heat and electricity.
- 17. a positive ion
- 18. a substance that cannot be decomposed into simpler substances by chemical or physical means. It consists of atoms all having the same atomic number. Graphite- carbon based: material that makes up pencil “lead”
- 21. a bonded collection of two or more atoms of the same element or different elements
- 22. a negative ion