Across
- 3. horizontal rows of elements
- 5. a pure substance that cannot be broken down
- 6. the number of protons in an atom's nucleus
- 8. the average mass of an atom as it occurs naturally
- 9. vertical columns; elements in the same group share similar properties
Down
- 1. elements that are usually shiny and conduct heat and electricity well
- 2. elements that are typically dull, brittle and poor conductors
- 4. the smallest particle of an element that maintains its properties
- 7. elements that have properties of metals and nonmetals