Question 1

A practical application of the wave nature of electrons is the

Accepted Answer

The electron microscope is a practical application of the wave nature of electrons. It uses a beam of electrons to create an image of a specimen, and the wavelength of the electrons determines the resolution of the image.

Question 2

How many electrons are there in the third shell of sodium,Na (atomic number 11)?

Accepted Answer

Sodium (Na) has an atomic number of 11, meaning it has 11 electrons. The electron configuration for sodium is 1s² 2s² 2p⁶ 3s¹, indicating that there is one electron in the third shell (3s orbital).

Question 3

According to the shell model,how many shells are required to describe the periodic table?

Accepted Answer

The periodic table is described using seven shells according to the shell model, correlating with the seven periods (rows) of the table.

Question 4

Oxygen,O,(number 8),sulfur,S,(number 16),and selenium,Se,(number 34)have such similar chemical properties because

Accepted Answer

The chemical properties of elements depend largely on the number and arrangement of electrons in their outermost shell. Oxygen, sulfur, and selenium all have six electrons in their outermost shell, making them similar in chemical properties. The fact that they are located close to each other in the periodic table supports this, but it is ultimately due to their electron configuration. Option D is incorrect because elements can have similar chemical properties even if they are in different periods of the periodic table, as long as they have similar outer electron configurations.

Question 5

What is the valence shell?

Accepted Answer

The valence shell is the outermost shell of electrons in an atom. This shell determines the chemical behavior of an atom and its reactivity in chemical reactions. The number of electrons in the valence shell also determines the element's position in the periodic table and its properties.

Question 6

In some instances electromagnetic radiation behaves like a wave.In other instances electromagnetic radiation behaves more like a particle.Which behavior more accurately describes the true nature of electromagnetic radiation?

Accepted Answer

Electromagnetic radiation behaves both as a wave or as a particle depending on the circumstance. This is known as wave-particle duality, and the behavior of electromagnetic radiation is best described as a combination of both wave-like and particle-like behavior, depending on the specific experiment or observation being performed. For example, in the photoelectric effect, electromagnetic radiation behaves as a particle (called a photon), while in diffraction and interference experiments, electromagnetic radiation behaves as a wave.

Question 7

The shell model is an example of a

Accepted Answer

The shell model is a conceptual model used in atomic physics to describe the structure of an atom's nucleus. It is not a physical model, as it does not involve a tangible representation of the atom.

Question 8

How does the wave model of electrons orbiting the nucleus account for the fact that the electrons can have only discrete energy values?

Accepted Answer

According to the wave model of electrons, when an electron wave is confined, it is reinforced only at particular frequencies. These frequencies correspond to the discrete energy values at which electrons can exist within an atom. So, the wave model can account for the fact that electrons can have only discrete energy values.

Question 9

What subatomic particle by itself is least affected by electromagnetic radiation?

Accepted Answer

Neutrons have no charge, so they are not affected by electromagnetic radiation, which interacts with charged particles. Electrons are heavily affected by it since they have a negative charge and are very small. Protons and the nucleus overall would be affected to a lesser extent, but still more than neutrons since they have a positive charge.

Question 10

The shell model presented in this book is not very accurate.Why then is it presented?

Accepted Answer

The shell model is presented because it is simpler and easier to understand, even though it is not very accurate.

Question 11

An atom absorbs or emits only particular frequencies of light.White light bends into a glass prism and separates into a rainbow of colors.In which of these two scenarios does the electromagnetic radiation behave as a wave? As a particle?

Accepted Answer

Absorption of light by atoms is best explained by the particle nature of light, where photons are absorbed by electrons to move to higher energy levels. The bending of light, or refraction, as it passes through a prism is explained by the wave nature of light, where different frequencies (colors) of light bend at different angles due to their varying wavelengths.

Question 12

Which of the following might best explain the reason why electrons are restricted to certain energy levels in an atom?

Accepted Answer

Electrons are restricted to certain energy levels in an atom because they exhibit wave-like behavior, which allows them to exist only in orbits where they can form standing waves. This self-reinforcing wave pattern restricts them to specific energy levels.

Question 13

How is it possible to deduce the identity of an element from its electron configuration?

Accepted Answer

The number of electrons in an atom's electron configuration corresponds to the atom's atomic number. If the atom is electrically neutral, the number of electrons will also be equal to the number of protons in the nucleus.

Answer: C
 Using the periodic table, one can determine the number of valence electrons in an atom based on its group, which is indicated by the outermost occupied shell. The number of occupied shells indicates the period or energy level of the atom.

Therefore, choices B and C are both valid explanations.

Question 14

Does a shell have to contain electrons in order to exist?

Accepted Answer

B and C are both reasonable answers. B explains that a shell is a region where electrons can be found, but it doesn't necessarily have to contain electrons to exist. C highlights that the concept of a shell is a model used in quantum mechanics and chemistry to describe the behavior of electrons around an atom, which means it's a theoretical construct rather than a physical entity that requires electrons to exist.

Question 15

What do the electron configurations for all the group 18 noble gases have in common?

Accepted Answer

The electron configurations for all the group 18 noble gases share the characteristic that their outermost occupied shells are filled to capacity, which is what makes them chemically inert or non-reactive.

Question 16

According to the shell model,which electrons play the most significant role in determining the properties of an atom?

Accepted Answer

The outermost electrons, also known as valence electrons, are the ones involved in chemical bonding and determining the chemical properties of an atom. Electrons in the innermost shell are tightly bound to the nucleus and not involved in chemical reactions. Electrons in the middle shells have some involvement in chemical bonding, but not to the same extent as the valence electrons in the outermost shell. Therefore, choice C is the correct answer.

Question 17

Some older cars vibrate loudly when driving at particular speeds.For example,at 65 mph the car may be most quiet,but at 60 mph the car rattles uncomfortably.How is this analogous to the quantized energy levels of an electron in an atom?

Accepted Answer

The vibrating car analogy is similar to an electron's energy level where specific conditions (speeds for the car, energy levels for the electron) result in resonance or a stable state, illustrating how electrons only occupy certain quantized energy levels.

Quiz 12: Atoms and the Periodic Table