The Modern Atomic Theory Assignment and Quiz

Which statement describes a major drawback of the Bohr model that caused scientists to replace it?

It contradicted the Heisenberg uncertainty principl

Which atomic model states that it is impossible to know the exact location of electrons around the nucleus?

electron-cloud model

Describe the photoelectric effect and explain why it made modifications to the Rutherford model necessary.

According to the Rutherford model, light of any energy should be able to make electrons leave the atom and be emitted. The energy of the emitted electrons should be related to the intensity of the light. Electrons are emitted only for certain wavelengths, and those wavelengths vary from atom to atom. The energy of the emitted electrons depends on the energy of the light, not its intensity.

Which event would be impossible to explain by using John Dalton's model of the atom?

An iron atom emits particles when it is struck by light.

Compare the modern (electron cloud) model of the atom with Dalton's atomic model. Which of these statements describe the two models correctly? Check all of the boxes that apply.

Dalton's model represented atoms as indivisible, but the modern theory recognizes that they contain smaller particles. The modern model explains all available data about atoms; Dalton's model does not.

Which equation was used by Albert Einstein to explain the photoelectric effect? [E = energy, h = Planck's constant, and v = frequency.]

E = hv

Which statement about Niels Bohr's atomic model is true?

Each orbit has a specific energy level.

The Bohr model of the atom explained why emission spectra are discrete. It could also be used to explain the photoelectric effect. Which is a correct explanation of the photoelectric effect according to the model?

Electrons need specific amounts of energy to jump levels and be emitted.

The diagram shows Niels Bohr's model of an atom. mc010-1.jpg What happens when the electron moves from the first energy level to the second energy level?

Energy is absorbed by the atom.

Describe the main difference between the Bohr model and the electron cloud model of the atom.

In the Bohr model, an electron's position is known precisely because it orbits the nucleus in a fixed path. In the electron cloud model, the electron's position cannot be known precisely. Only its probable location can be known.

Scientists made the following two observations about emission spectra: Each element has a unique emission spectrum. Atoms emit energy only at specific wavelengths. Describe how the Bohr model explains both of these observations.

In the Bohr model, electrons can exist only in certain energy levels surrounding the atom. When electrons jump from a higher energy level to a lower one, they emit light at a wavelength that corresponds to the energy difference between the levels. The energy levels in each atom are unique.

Describe the main difference between the Bohr model of the atom and the Rutherford model.

In the Rutherford model, electrons can exist in any location outside the nucleus. In the Bohr model, electrons can exist only in certain energy levels surrounding the atom.

Which statement about the electron-cloud model is true?

It is the currently accepted atomic model.

The modern-day quantum model of the atom is better than John Dalton's model because it

answers many questions about atoms.

Natalie observes these characteristics in the model of an atom. (i) includes positive charge (ii) contains electrons (iii) explains the photoelectric effect (iv) suggests the probable location of electrons Which model is Natalie most likely examining?

electron-cloud model