U1L1: The Modern Atomic Theory

How does the electron-cloud model describe electrons? The exact position of an electron can be known. An electron can be found at certain distances from the nucleus. An electron has a high probability of being in certain regions. Each electron follows a specific path around the nucleus.

An electron has a high probability of being in certain regions.

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. An oxygen atom combines with two hydrogen atoms to form water. An acid reacts with a base to form salt and water. The atoms in sodium metal react with water.

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

Check the statements that are a part of the Early Atomic Theory. Check all of the boxes that apply. Scientists believe that the atom is made up of elements. Atoms combine in whole number ratios to form compounds. Atoms cannot be created or destroyed during a chemical reaction.

Atoms combine in whole number ratios to form compounds. Atoms cannot be created or destroyed during a chemical reaction.

Electrons orbit the nucleus in specific, defined paths. Each path has a specified energy. Bohr model electron cloud model Dalton model

Bohr model

Identify each of the atomic models described here. Atoms are indivisible spheres. plum pudding model Dalton model Bohr model

Dalton model

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 was replaced only because of its age. 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. The modern model is more widely accepted because it was proposed by more well known scientists.

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.

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

Did your answer include all of the following? 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.

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

Did your answer include all of the following? 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.

Did your answer include all of the following? 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.

Did your answer include all of the following? 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 equation was used by Albert Einstein to explain the photoelectric effect? [E = energy, h = Planck's constant, and v = frequency.] E = h/v E = hv E = v/h E = h - v

E = hv

Which statement about Niels Bohr's atomic model is true? Higher orbits have lower energies. Each orbit has a specific energy level. Electrons can exist in any energy level. Orbits close to the nucleus have no energy.

Each orbit has a specific energy level.

The diagram shows Niels Bohr's model of an atom. What happens when the electron moves from the first energy level to the second energy level? Energy is absorbed, and an emission line is produced. Energy is released, and an emission line is produced. Energy is absorbed by the atom. Energy is lost from the atom.

Energy is absorbed by the atom.

Mark the statement as true or false. All of the proposed ideas by Dalton, Thompson, and Rutherford are still used in the Modern Theory of the Atom. True False

False

Which statement describes a major drawback of the Bohr model that caused scientists to replace it? It worked only for helium and larger atoms. It did not identify the distance between an electron and the nucleus. It contradicted the Heisenberg uncertainty principle. It stated that spectral lines of atoms are similar.

It contradicted the Heisenberg uncertainty principle.

Which statement about the electron-cloud model is true? It is the currently accepted atomic model. It can easily be replaced by existing models. It specifies the location and momentum of an electron. It does not explain the formation of emission lines.

It is the currently accepted atomic model.

emission spectrum

an electromagnetic radiation spectrum in which wavelengths of light emitted by a substance show up as brightly colored lines on a black background

This flow chart shows the amount of energy that is emitted by each type of light. ultraviolet > blue light > yellow light > red light (maximum energy) (minimum energy) In an experiment, shining which type of light on a strip of metal would be least likely to produce the photoelectric effect? ultraviolet light dim blue light bright red light bright yellow light

bright red light

An electron's position cannot be known precisely. Only its probability of being in a certain location can be known. Bohr model plum pudding model electron cloud model

electron cloud model

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? Bohr model Dalton's model plum pudding model electron-cloud model

electron-cloud model

A hydrogen electron is elevated from level 1 to level 2. Another electron is elevated from level 2 to level 4. The transition requiring the greatest energy change is ___

level 2 to level 4

Light is emitted by electrons when they drop from one energy level to a lower level. Which transition results in the emission of light with the greatest energy? level 2 to level 1 level 3 to level 2 level 4 to level 2

level 4 to level 2

Electrons are embedded in a mass of positively charged matter. electron cloud model plum pudding model Dalton model

plum pudding model

Blue light waves have more energy than red light waves. Which of these situations most likely produces a photoelectric effect? You may assume that the same metal is used in each situation. Check all that apply. shining dim red light on a strip of metal shining bright red light on a strip of metal shining dim blue light on a strip of metal shining bright blue light on a strip of metal

shining dim blue light on a strip of metal shining bright blue light on a strip of metal

electron cloud model

the modern model of atomic structure in which protons and neutrons make up the very dense, tiny nucleus, and electrons surround the nucleus in clouds of probable locations

photoelectric effect

the process in which matter emits electrons as the result of absorbing light

Light of a certain energy shines on a metal and causes electrons to be emitted. Based on the research of Albert Einstein, what change would most likely result in stopping the emission of electrons from this metal? an increase in the intensity of the light a decrease in the intensity of the light the use of light that has a higher frequency the use of light that has a lower frequency

the use of light that has a higher frequency

Light shining on a strip of metal can dislodge electrons. Do you think this is more consistent with light being made up of waves or of particles? waves particles not sure

whatever you want :/ i put particles