Solve these clues to fill the grid.
- Hopeful and optimistic; the opposite of negative
- 4 Across
- A body having finite mass and internal structure but negligible dimensions (plural)
- 7 Across
- An elementary particle with negative charge
- 8 Across
- An elementary particle with 0 charge and mass about equal to a proton (plural)
- 9 Across
- A pleading describing some wrong or offense (plural)
- 10 Across
- Any of several chemical elements that are usually shiny solids that conduct heat or electricity (plural)
- 11 Across
- A stable particle with positive charge equal to the negative charge of an electron (plural)
- 14 Across
- The simplest structural unit of an element or compound
- 1 Down
- A piece of photographic film showing an image with light and shade or colors reversed
- 2 Down
- That which has mass and occupies space
- 3 Down
- A well-substantiated explanation of some aspect of the natural world
- 5 Down
- An abstract part of something (plural)
- 6 Down
- Center of an atom or a cell
- 9 Down
- The smallest component of an element having the chemical properties of the element
- 12 Down
- A hypothetical description of a complex entity or process (plural)
- 13 Down
- A line or route along which something travels or moves
- 14 Down