Since atoms could not be observed directly in the late 1800\'s and early 1900\'s
ID: 1291267 • Letter: S
Question
Since atoms could not be observed directly in the late 1800's and early 1900's, scientists and philosophers adhering to the logical positivist view thought
A. it would never be possible to observe them.
B. they were therefore not real.
C. they were not at all useful to think about.
D. they could be sensed with ESP.
2. The first theoretical model which could predict the spectrum of hydrogen correctly was
A. the Rutherford planetary model of the atom.
B. the Einstein model of the atom.
C. the Bohr model of the atom, with discrete orbits.
D. the "plum pudding" model of the atom.
E. the "raisin bran" model of the atom.
3. Mendeleyev's periodic table of the elements
A. organized elements according to their electromagnetic properties
B. explains why gases emit dark bands of light.
C. was an empirical classification of chemical elements.
D. was forgotten for decades, then rediscovered.
E. was instantly adopted by the chemistry community.
4. Evidence of the internal structure of atoms was given by (Check all correct answers)
A. the existence of radioactivity
B. the theory of quantum mechanics
C. a knowledge of equivalent atomic masses
D. the discovery of electrons
E. the periodic table
5. The model of the atom which had electrons embedded inside a sphere of positive charge was the
A. Rutherford model.
B. plum pudding model.
C. planetary model.
D. Avogadro model
6. What ancient Greek philosopher is credited with the idea of the atom?
A. Anaxagoras
B. Dalton
C. Eudoxus
D. Pythagoras
E. Democritus
7. A photon has an energy of 3.6 x 10-19J. What is it's frequency?
_____Hz
8. When an electron in an atom jumps from a level with energy -5.4 eV to one of energy -7.5 eV, what is the energy of the photon that is emitted?
____eV
Explanation / Answer
1. Since atoms could not be observed directly in the late 1800's and early 1900's, scientists and philosophers adhering to the logical positivist view thought
Answer B. they were therefore not real.
2. Answer- A. the Rutherford planetary model of the atom.
3. D. was forgotten for decades, then rediscovered.
4. C. a knowledge of equivalent atomic masses
5. B. plum pudding model.
6.E. Democritus
7. Since, energy= h*frequency
so, frequency= (3.6*10^-19)/6.626*10^-34=5.433*10^15 Hz ......(answer)
8. Energy= difference in energy level= 7.5-5.4= 2.1 eV