Assignment 25561

Which of the following main points of John Dalton’s atomic theory are still accepted by modern scientists?
all matter is made up of atoms
atoms are indestructible
atoms of one element are all exactly alike
all atoms are indivisible
7. Which of the following statements is correct?
All atoms are electrically neutral.
All atoms are negatively charged.
All isotopes are positively charged.
All elements have an electrical charge.
8. Which of the following statements characterize the atomic nucleus of the atom?
I. It has a positive charge.
II. It is very small in size but very dense.
III. It contains protons, neutrons, and electrons.
I and II only
I and III only
II and III only
I, III, and III
9. Which of the following is the most accurate definition of an element?
a pure substance that cannot be separated into simpler substances by physical or chemical means
the most basic building block of matter
the particles that make up atoms
a combination of two or more atoms that are chemically combined
11. Compare the structure and numbers of subatomic particles in an electrically neutral atom of carbon and an isotope of carbon.
13. If two atoms have the same mass numbers but different atomic numbers, then they can be considered atoms of the same element.
True
False
15. The nucleus of the atom is held together by the mutual attraction of the positively charged protons and the negatively charged neutrons.
True
False
18. Match the scientist to his contribution to quantum theory:
theorized that light energy can either be released or absorbed in discrete packets known as “quanta”
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described all radiant energy as behaving like a stream of particles
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proposed the Uncertainty Principle
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suggested that electrons could move as particles and as waves
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theorized that electrons moved about the nucleus in fixed orbits; Known as the “Planetary Model”
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Answer
A.
Louis deBroglie
B.
Max Planck
C.
Werner Heisenberg
D.
Albert Einstein
E.
Niels Bohr
19. Of the many theoretical contributions to the quantum theory, one of the contributions was the “uncertainty principle”. Which of the following statements describes the essence of this principle?
Electrons exist in discrete energy levels, described by quantum numbers
Energy must be added to move an electron to a level further away from the nucleus and removed to move an electron closer to the nucleus
Radiant energy is quantized
Due to the dual nature of electrons, we cannot simultaneously know an electron’s position and its momentum (path). Measuring one changes the other.
21. The wave mechanical model of electron behavior helped to explain:
that an electron can be defined by its energy, frequency or wavelength
that electrons always acted as particles and never like waves
why Rutherford’s model was superior to Bohr’s in explaining electron behavior
why electrons can never be moved from their original orbits
23. The sublevel that has the largest number of differently shaped orbitals is the f sublevel.
True
False
24. As a general rule, the lower energy sublevels of a main energy level are filled before placing electrons in the higher energy sublevels.
True
False
26. The fact that the 2s orbital would fill with electrons before the 2p orbital would accept electrons is an application of:
the Aufbau principle
Hund’s rule
the Pauli exclusion principle
Schrödinger’s equation
27. Describe the orbital notation and electron configuration notation to describe the placement of all of the electrons in an atom of Fluorine.
29. Radiant energy is emitted when an electron of a particular atom jumps from a higher energy level to a lower energy level. If the energy released by the transition is 3.68 x 10-19 J, what atom is most likely involved?
Copper – Green Light (approximately 520-565 nm)
Barium – Yellow Light (approximately 565-590 nm)
Sodium – Red-Orange Light (approximately 615-635 nm)
Potassium – Violet Light (approximately 380-420 nm)
30. What is the location of the last electron of the sodium atom?
3s0
3s2
2p6
3s1
31. Match the following energy levels with the proper description.
4 d
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5 f
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7 s
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5:00 PM
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Answer
A.
Contains the lowest main energy level
B.
Contains the sublevel with the least number of atomic orbitals
C.
Contains the highest sublevel
D.
Contains the sublevel that may hold up to 6 electrons when it is full
32. Classical mechanics analytically describes the motion of all objects on the macroscopic scale, but does not apply well at the subatomic level.
True
False
33. Classical mechanics is based on the principle of uncertainty, and predicts all phenomena in terms of probabilities. It describes a sub-atomic world, which is totally different from the world at macroscopic scales.
True
False
34. Areas in which discrepancies were observed between classical mechanics and quantum mechanics are: blackbody radiation and the photoelectric effect.
True
False