Atomic world

2. A subatomic particle in an atom's nucleus that has a positive charge of 1+.
5. The extremely small, positively charged, dense center of an atom that contains positively charged protons and neutral neutrons.
7. The number of protons in an atom.
9. Protons have a _______ charge
12. When atoms arrange themselves to form a new substance
14. Electrons have ______ charge
16. A negatively charged, particle with an extremely small mass has a charge of -1
18. The smallest particle of an element that retains all the properties of that element
19. Power which must be transformed into motion

1. Discovered the electron.
3. An atom located in the outermost shell of an atom
4. Discovered the nuecleus and the proton
6. The number of protons plus neutrons in an atom.
8. designed the periodic table
10. My teacher calls himself
11. A subatomic particle in an atom's nucleus that has a positive charge of 0.
13. Unit of matter with more or fewer electrons or protons
15. Atoms of the same element with different numbers of neutrons.
17. Composed of atoms with the same atomic mass
18. a unit of mass, equal to 1/12 the mass of the carbon-12 atom and expresses the mass of atomic and subatomic particles.