Download Atomic Theory and Models Outline Notes

Atomic Theory and Models Outline Notes
I.
Atomic Models:
A. This model of the atom is the “Bohr model”. In this model…
B. Atomic Models through Time - The atomic model has changed throughout …
II.
Scientists of Atomic Theories
A. Democritus
1. This is the Greek philosopher Democritus who began the search for a description of matter
more than ______________ years ago.
2. His theory –
3. He named the smallest piece of matter “_________________,” meaning
“_________________________________.”
4. Atoms were infinite in number…
B. John Dalton
1. In the early 1800s, the English Chemist John Dalton performed a number of experiments
that eventually…
2. The main points of Dalton's atomic theory are:
C. J.J. Thomson
1. In 1897, the English scientist J.J. Thomson provided the first hint that an atom is made of
even smaller particles
2. He proposed a model of the atom that is sometimes called ________________________
_________________________________
3. Atoms were made from a positively charged substance with negatively charged electrons
scattered about, ____________________________________________________________
4. Thomson studied ___________________________________________________________
5. As the current passed through the gas __________________________________________
__________________________________________________________________________
6. Thomson concluded that the negative charges came from __________________________
7. A particle smaller than an atom had to exist.
8. Thomson called the negatively charged “__________________,” today known as
__________________
D. Ernest Rutherford (year:
)
1. Also conducted experiments to study the atom. He found that atoms have a nucleus –
2. His work also concluded…
3. Rutherford’s experiment involved firing a stream of tiny positively charged particles at a
__________________________________________
4. This could only mean that the gold atoms in the sheet were mostly ___________________
5. The nucleus is tiny compared __________________________________________________
6. Rutherford’s Conclusion: Rutherford reasoned that all of an atom’s positively charged
particles were contained in the nucleus. The negatively charged particles ______________
__________________________________________________________________________
E. Neils Bohr (year:
)
1. In his model, he placed each electron
2. Bohr Model - According to Bohr’s atomic model, electrons move in
F. Modern Theory - Wave or the Quantum Model
1. Today’s atomic model is based on the
2. According to the theory of wave mechanics,
3. In fact, it is impossible to determine the exact location of an electron. The probable
location of an electron is based on
4. According to the modern atomic model, at atom has a small positively charged nucleus
surrounded by a large region in which there are
III.
Electron Clouds
1.
2.
3.
4.
IV.
Energy and the Electron Cloud
1.
2.
3.
4.
V.
Electrons have special rules:
1. Bohr models atoms’ electrons organized into ___________________________.
2. Each level can hold a ____________________________ of electrons
3. The first energy level can hold up to _________________________
4. 2nd energy level – (up to) ____________________________
5. Electrons are not usually added to energy levels until the ____________________ are filled
6. The electrons in the outer most shell of any element are called _________________________
VI.
Octet Rule
A. Rule of 8
1.
All atoms want
2.
Atoms with less than 8 electrons
3.
In general, the fewer the electrons that need to be gained or lost,
B. More on Energy Levels
C. Exception to the Rule
1. In the Bohr Model of the atom, _____________ fill different electron ______________
(also known as electron shells or energy levels) from the _________________________.
2. The first orbital can only hold ____________________. The second orbital can hold
________________________, the third can hold up to __________, and the fourth up to
__________, but the outermost orbital can never have more than ___________________.
3. Only these ___________________________, known as __________________ electrons,
can ____________________________________________________________________.
D. Valence Electrons
1. The electrons farthest away from the nucleus in the “_______________________________”
are called __________________________
a. They affect the way an ________________________
b. Different atoms have a different number of ________________________________
c. Atoms can have anywhere _________________________________ valence electrons
E. Lewis Structure
1. The Lewis structure is used to ________________________________________________
of a molecule or ion
2. When an element is alone, ___________________________________________________
F. Limitations of the Bohr Model: