Chapter 4 – Introduction to Atoms

1. Chapter 4 – Introduction to Atoms

2. Section 1 – Development of the Atomic Theory • __________= smallest particle which an element can be divided and still be the same substance - __________ make up elements - elements combine to form __________ - atoms called the building blocks of life

3. ____________ = unifying explanation for a broad range of hypotheses and observations, supported by testing

4. __________________ proposes atom (uncuttable part of something) • _______________disagrees (popular)

5. ______________  creates atomic theory; revised as new info is found

6. Dalton’s Atomic Theory • All substances made up of atoms. Atoms are small particles that cannot be created, divided or destroyed • Atoms of same elements are identical, atoms of diff. elements are diff. • Atoms join with other atoms to form new substances

7. ______________ small particles inside an atom, particles with negative charge - What are these things called with a negative charge? ____________________ - Where are they located? ___________________________________

8. Thomson’s Experiment

9. _________________  used a gold foil experiment to discover there was a small massive thing inside of an atom - What is this thing called in the center of an atom? _____________________ - Remember from the video that most of the atom is made up of ______________ ______________

11. __________  says that e- can jump from level to level - but they do have definite paths, is this true? • ______________ & ________________  exact path of an e- _______ ______ be predicted therefore we call them e- ________

14. Section 2 – The Atom • Average sized atom has diamter = .000000003 cm (3 hundred-millionths) • 50,000 Al atoms to equal the thickness of a sheet of ________________ ________ • Penny contains 2 x 10 22 atoms - Amazingly enough this is 3,000,000,000,000x the number of people on the planet

15. Inside of an atom: 1) Proton= located in the _____________ - _____ amu - _____ is its charge 2) Neutron = located in the ____________ - _____ amu - _____ is its charge • Most mass is found in the _____________ • Connection to the ________ _____________

17. 3) Electrons = located ______________ of the nucleus in _________, _________ or ___________ - ______ amu - ______ is its charge • How do you find the # of P? • How do you find the # of e-? • How do you find the # of N?

18. ___________ = an atom that has gained a charge to the loss or gain of a(n) ___________ • ___________ = an atom with the same number of protons (so it is still the same element), but a diff. # of _________________ - Some isotopes unstable  which means they are ________________________ - Most isotopes share same properties - How can you tell something is an isotope? What do you have to have? Ex: C – 12 vs C – 13 vs C – 14

20. __________ _______ = weighted average of all of the naturally occurring isotopes, so this explains why it is a ________________

21. Four Forces Keep Atoms together 1) ______________ = most familiar force, but it is very small b/c of what we know about it 2)_______________________ = unlike charges __________ and like charges _______ 3) __________ _________ = P pushing away from each other, but this force keeps the _________________ together 4) _________ _________ = important in radioactive atoms, plays a role in a N changing into a P