Atoms and Periodic Table

2. an arrangement of elements
5. vertical columns in the periodic table
7. a particle with a positive or negative charge
8. group of atoms held together by chemical bonds
9. poor conductors of heat and electricity
12. horizontal rows in the periodic table
15. interaction that holds atoms or ions together
17. what is the mass number of an isotope of an atom with 2 neutrons and 1 proton
18. center of the atom
20. number the number of protons in the nucleus
21. a force that brings oppositely charged ions together
22. area that consists of electrons
23. has no charge
25. smallest particle an element can be divided into

1. electrons found in the outermost level
3. what separates the metals from nonmetals on the periodic table
4. has a negative charge
6. what is the atomic number of a sodium atom that has 11 protons and 12 neutrons
8. number the total number of protons and neutrons in an atom
10. the total amount of electrons the first energy level can hold
11. atoms that share one or more pairs of electrons
12. has a positive charge
13. the total amount of electrons the second energy level can hold
14. elements that have properties of both metals and nonmetals
16. bonds between metal atoms when their outermost energy levels overlap
19. abbreviation for an element
24. elements that are shiny and conduct heat well