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Name _____________________________________________ date _________ period _____
Physical Science
Unit 8
Atoms
Chapter 4
1. Atomic Structure – timeline - Ancient ________________ - Democritus proposed the ____________
– a tiny solid particle that could not be _____________________.
2. 1904 – J.J. _________________ – discovered that atoms contained small, ________________
charged particles called ____________________________.
3. 1911 – Ernest ______________________ – proposed that the atom had ____________ parts – the
_______________________ in the center (most of the mass) surrounded by the
___________________.
4. _________________________ Atomic Theory –a) Every ___________________ is made of tiny,
unique, particles called ________________ that cannot be _____________________. b) Atoms of
the same _____________________ are exactly _________________. c) Atoms of __________
elements can _______________________ to form ________________________
5. 1913 – Niels _________________ – hypothesized that ___________________ traveled in fixed
_______________________ around the atom’s nucleus.
6. 1913 – James _______________________ – concluded that the _________________ contained
positive _______________________ and neutral ___________________________.
7. 1926 – Erwin _________________________ – developed the ___________________ mechanical
model – which is based on the wavelike properties of the ________________. (not a particle – leads
to quantum physics).
8. 1927 – Werner ______________________ – (the Heisenberg uncertainty Principle) described that it
is _____________________________ to know precisely both an electron’s ____________ and path
at a given time. Led to the electron _____________________ theory
9. Atoms - The ____________________________ particle that has the properties of an element.
10. Parts of an Atom - _____________________ – small, dense ____________________ of an atom
made up of ____ subatomic particles that are almost ____________________ in size and mass.
_____________________ – have a positive charge. ___________________ – have no charge.
11. _________________________ – are tiny particles that have very little ____________ that moves
around the _____________________ of the ______________________. These particles are
__________________________ charged and form a “________________” around the nucleus.
12. The number of ______________________ and ________________________ an atom has is unique
for each element.
13. Atomic _______________________ - Atoms have ________ overall charge because the _______ (+)
cancel out the _____________________ (-)
14. Protons - _________________ (+) charge - Found in the __________________ - # of protons =
________________ # - The number of protons ____________________ the element (atomic #)
15. Neutrons - ________ charge - Found in the ____________________ - Along with protons makes
up atomic _______________
16. Electrons - ______________________ (–) charge - travel in ____________________ (or energy
levels) around the nucleus. (electron cloud) - _____________________ electrons - the # of
electrons in the outer shell = ___________________________ #
17. Unit of _____________________ for atomic particles is Atomic mass unit (___________) protons
and neutrons = about ____ amu (electrons are about the size of 1 __________________)
18. Chemical ______________________ - The one or two ___________________ abbreviation of the
element name.
19. _______________ Number or _________________ Mass - the __________ of the number of
protons and the number of neutrons in the _____________________ of an atom. - # of
neutrons = mass # - _________________ #
20. _______________________ atomic mass - the weighted - average ____________ of the mixture of
all an atoms _______________________. The average atomic mass is ______________ to the mass
of its most __________________________ isotope.
Example: Identify the Number of Protons, Neutrons and Electrons in Oxygen
Example 2: Identify the Number of Protons, Neutrons and Electrons in Sulfur and Sodium
21. Isotopes - Atoms of the ______________________ element that have a ____________________ # of
___________________________. (identified by the element name followed by the mass # ) ex. C12, C-_____, B-10, B-_____)
22. ________________ _____________ mass is the weighted - average mass of the mixture of all an
atoms isotopes. The average atomic mass is close to the mass of its most abundant isotope.
23. This is the number found on the _________________________
24. Bohr was the 1st person to propose the concept of electrons having specific _______________
25. This explained how electrons could give off light ( by gain or lose energy)
26. Bohr’s Model can be used to show how the electrons will arrange themselves around
a__________________
27. Electrons are placed in energy levels surrounding the nucleus. You fill the lower energy levels first
28. The 1st energy level can hold max of ______ electrons
29. The 2nd energy level can hold max of ______ electrons
30. The 3rd energy level can hold max of _____ electrons
31. The 4th energy level can hold max of _____ electrons
32. Example Chlorine:
33. _________________________Electrons: Electrons found in outer energy level.
34. Chlorine has _____ valance electrons in outer energy level .