Atomic Structure

3. substance that cannot be broken down into any other substance
4. the ability to attract and repel subatomic particles depends on this
6. combination of 2 or more atoms bonded together
9. center of the atom containing positive and neutral particles
10. substance made of 2 or more elements chemically combined
12. arrangement of elements in order of atomic number
14. neutrally charged particle in the nucleus of the atom
15. vertical columns on the periodic table
17. set of characters that is used to identify an element
18. description of the structure of the atom, proposed in 1913 by a Danish physicist
19. negatively charged particle outside the nucleus

1. sum of the protons and neutrons in an atom
2. negatively charged particles in the outer energy shell
5. number of positively charged particles in an atom
7. atom with odd number of neutrons compared to protons
8. area inside the atom but outside the nucleus where negatively charged particles are found
11. a charged particle
12. positively charged particle in the nucleus of the atom
13. the smallest particle of matter
16. horizontal rows on the periodic table