Chemistry Chapter: Atomic Theories

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Questions and Answers

What did Rutherford propose about the nucleus of an atom?

Rutherford proposed that the nucleus contains most of the atom's mass and positive charge in a very small volume.

How did Rutherford describe the arrangement of electrons in his atomic model?

Rutherford described electrons as revolving around the nucleus in circular paths called orbits.

What force keeps the electrons and nucleus together in the Rutherford model?

The electrons are held to the nucleus by a strong electrostatic force of attraction.

What limitation of the Rutherford atomic model was pointed out by Maxwell's theory?

Maxwell's theory indicated that accelerating charged particles, like electrons, would emit electromagnetic radiation and lose energy, causing them to collapse into the nucleus. Signup and view all the answers

What was a significant drawback of the Rutherford atomic model regarding the electrons?

A significant drawback was that Rutherford did not explain the arrangement of electrons within the atom. Signup and view all the answers

According to calculations related to Rutherford's model, how quickly would an electron collapse into the nucleus?

Calculations showed that an electron would collapse into the nucleus in less than $10^{-8}$ seconds. Signup and view all the answers

What did both Thomson's and Rutherford's atomic models fail to address?

Both models failed to explain the energy and stability of an atom. Signup and view all the answers

How did the early atomic models contribute to the development of quantum mechanics?

Despite their inaccuracies, early atomic models laid the foundational concepts that led to advancements in quantum mechanics. Signup and view all the answers

What is the relationship between atomic mass (A), atomic number (Z), and the number of neutrons (N)?

Atomic mass (A) is the sum of protons and neutrons, while neutrons (N) can be found using the equation N = A - Z. Signup and view all the answers

Define isotopes and give an example.

Isotopes are atoms of the same element with the same atomic number but different mass numbers; for example, Carbon-12 and Carbon-14. Signup and view all the answers

What distinguishes isotones from isotopes?

Isotones are nuclei with the same number of neutrons but different atomic numbers, whereas isotopes have the same atomic number but different neutron counts. Signup and view all the answers

Explain what isobars are and provide an example.

Isobars are atoms of different elements that have the same mass number but different atomic numbers; for example, Argon-40 and Calcium-40. Signup and view all the answers

What is the primary role of the nuclear force in an atomic nucleus?

The nuclear force binds protons and neutrons together in the nucleus, overcoming the repulsive electric force between protons. Signup and view all the answers

How does the strength of the nuclear force compare to other fundamental forces?

The nuclear force is approximately 10 million times stronger than chemical binding forces. Signup and view all the answers

What are the three types of nucleon interactions mentioned in the context of nuclear force?

The interactions are between protons and protons, neutrons and protons, and neutrons and neutrons. Signup and view all the answers

What does the term 'atomic number' (Z) represent in nuclear physics?

Atomic number (Z) represents the number of protons present in the nucleus of an atom. Signup and view all the answers

What property of nuclear force allows it to bind protons together despite their repulsive nature?

The attractive nature of nuclear force allows it to bind protons together, overcoming their Coulomb repulsion. Signup and view all the answers

At what distance does the nuclear force become practically non-existent?

The nuclear force becomes practically non-existent at distances greater than 2.5 Fermi. Signup and view all the answers

How does the nuclear force behave at distances less than 0.7 Fermi?

At distances less than 0.7 Fermi, the nuclear force becomes repulsive. Signup and view all the answers

What are the two subatomic particles that comprise the nucleus of an atom?

The nucleus of an atom is comprised of neutrons and protons. Signup and view all the answers

What are the two processes through which nuclear energy is released?

Nuclear energy is released through nuclear fission and fusion. Signup and view all the answers

What role does the repulsive component of nuclear force play in the size of the nucleus?

The repulsive component of nuclear force limits how closely nucleons can pack together, thereby determining the size of the nucleus. Signup and view all the answers

How does nuclear fusion differ from nuclear fission?

Nuclear fusion involves combining atoms to form a larger atom, while nuclear fission involves splitting larger atoms into smaller ones. Signup and view all the answers

What effect does the Coulomb resistance have on the nuclear force?

Coulomb resistance affects the nuclear force by creating a repulsive effect between protons, necessitating a strong enough nuclear force to keep them bound. Signup and view all the answers

What is mass defect and how is it calculated?

Mass defect is the difference between the actual atomic mass and the predicted mass of nucleons. It can be calculated using the formula $𝚫M = (Zmp + Nmn) – MA$. Signup and view all the answers

How does the concept of binding energy relate to mass defect?

Binding energy is the energy released when a nucleus is formed, which accounts for the mass defect observed in the nucleus. It reflects the energy needed to separate constituents within the nucleus. Signup and view all the answers

List two applications of nuclear technology in medicine.

Two applications of nuclear technology in medicine are medical diagnosis and treatments, such as using radioactive isotopes in imaging and therapy. Signup and view all the answers

Explain the role of neutron activation analysis in scientific investigations.

Neutron activation analysis is used to determine the concentration of elements in a sample by irradiating it with neutrons and measuring the resulting radiation. Signup and view all the answers

What is the significance of mass defect in nuclear physics?

Mass defect is significant because it explains the stability of nuclei and the energy released during nuclear reactions. Signup and view all the answers

Identify one agricultural use of nuclear technology.

One agricultural use of nuclear technology is the development of pest-resistant crops through mutation breeding. Signup and view all the answers

Describe a role of nuclear technology in engineering projects.

Nuclear technology is used in engineering projects for processes such as non-destructive testing to ensure material integrity. Signup and view all the answers

What types of particles does binding energy concern in a nuclear context?

Binding energy concerns protons and neutrons within an atomic nucleus. Signup and view all the answers

What is the mass defect of the helium nucleus based on the given information?

0.02914 a.m.u. Signup and view all the answers

Calculate the binding energy of a helium nucleus in MeV.

27.129 MeV Signup and view all the answers

What is the binding energy per nucleon for a helium nucleus?

6.782 MeV Signup and view all the answers

What is the mass defect of the Li⁷ nucleus given the provided data?

0.032486 a.m.u. Signup and view all the answers

What is the binding energy of the Li⁷ nucleus in Joules?

3.96 x 10⁻¹¹ J Signup and view all the answers

What is the frequency of the photon emitted when a Hydrogen atom transitions from the first excited state to the ground state?

2.46 x 10¹⁵ Hz Signup and view all the answers

Identify the number of protons and neutrons in the Aluminum nucleus 27₁₃Al.

13 protons and 14 neutrons Signup and view all the answers

What is the energy of an electron in the first Bohr's orbit for a hydrogen atom?

-13.6 eV Signup and view all the answers

What is the energy of the photon emitted during the transition from n = 4 to n = 2 in a hydrogen atom?

2.55 eV Signup and view all the answers

Calculate the wavelength of the Hα line resulting from the transition from n = 3 to n = 2.

6513 Å Signup and view all the answers

What is the radius of the first orbit of the hydrogen atom according to Bohr's model?

0.53 Å Signup and view all the answers

Determine the binding energy per nucleon for helium.

7.07 MeV per nucleon Signup and view all the answers

What is the frequency of the photon emitted when a hydrogen atom transitions from -15 eV to -3.4 eV?

4.59 x 10^14 Hz Signup and view all the answers

Calculate the mass defect of uranium using the data provided.

1.87854 amu Signup and view all the answers

What is the second line wavelength of the Lyman series if the first line is at 1200 Å?

1012.5 Å Signup and view all the answers

What is the binding energy of the iron nucleus in MeV?

492.26 MeV Signup and view all the answers

Flashcards

Rutherford Atomic Model

A model of the atom with a positively charged nucleus at the center, surrounded by negatively charged electrons orbiting in circular paths.

Nucleus (atom)

The small, dense, positively charged central part of an atom.

Electron Orbits

The circular paths followed by electrons around the nucleus, as described in the Rutherford model.

Atomic Stability Problem

Rutherford's model couldn't explain how atoms don't collapse due to electrons losing energy and spiraling into the nucleus.