Atoms and molecules C.W .P

4. characteristics that are measurable or observable are called physical _____________.
6. the"electronic connections" between elements in a molecule.
8. this element is found in all organic matter and has four valence electrons.
10. "like"electric charges ____________________ each other.
11. are "shared" in this type of bond.
12. a group of elements with similar properties are known as a _________________.
13. number this matches the number of protons in an atom.
14. each ___________________ on the periodic table represents the number of valence electrons in an element.
17. electrons have a ______________________ charge.
20. subtract the atomic number from the atomic mass to find the number of _________________.
21. a combination of one or more atoms.
23. table the elements are organized into this grid.
25. formula nacl is the ___________________________ for salt.
26. an element that can have a variable number of neutrons in its nucleus.
27. reactivity is a ______________________ property.

1. protons have a _________________________ charge.
2. gasses a"Family" of elements that do not typically react with other elements.
3. the"outer energy shell" of and atom
5. cloud the location around the nucleus where electrons orbit.
7. when elements react they form new _____________________.
9. a charged particle.
15. the center of an atom where the protons and neutrons are located.
16. the"Family" of elements that are very reactive.
17. a neutron has a ___________________ charge.
18. electrons are "stolen" in this type of bond.
19. atoms with full outer energy shells are known to be _______________.
22. other than hydrogen and helium, the number of electrons needed to fill the valence shell.
24. each__________ on the Periodic Table represents the number of "energy levels" an element has.
25. symbol an abreviated way to name an element.