Atoms and the Periodic Table

2. Represents the identity of an element.
4. Positively charged center of the atom.
5. My atomic number is 47
6. I am a metalloid that usually has 71 neutrons
8. Smallest known particle that makes up protons and neutrons.
11. I am not a alkali metal, but I am in group 1.
12. The sum of protons and neutrons in an atom
14. Atoms of the same element with different masses
16. I am the 2nd most reactive metal
18. I am the only liquid metal at room temperature
19. All elements in the same one of these has the same number of energy levels in their electron cloud.
21. Negatively charged particles in the outermost energy level of the electron cloud.
24. I am a gas with 8 neutrons

1. Negatively charged particles in an atom.
3. Region surrounding the nucleus where electrons are found.
7. Positively charged particles in atoms.
9. I am the only noble gas without 8 valence electrons
10. Organizes elements by their properties
13. The smallest form of matter that still retains the properties of an element.
15. I have 28 electrons when electrically neutral
17. Particles that differ in number between isotopes
20. I have 26 protons
22. I have 6 valence electrons and 16 protons.
23. I am the only halogen with 5 energy levels
25. Verticle column in the periodic table