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Questions and Answers
The nucleus of an atom is composed of ______ and neutrons.
The nucleus of an atom is composed of ______ and neutrons.
protons
The number of protons in an atom's nucleus is called the ______ number.
The number of protons in an atom's nucleus is called the ______ number.
atomic
Atoms of the same element that have different numbers of neutrons are called ______.
Atoms of the same element that have different numbers of neutrons are called ______.
isotopes
The ______ model, an early model of the atom, described electrons as orbiting the nucleus in specific energy levels.
The ______ model, an early model of the atom, described electrons as orbiting the nucleus in specific energy levels.
Electrons can only occupy specific energy levels, and they must make ______ to transition between these levels.
Electrons can only occupy specific energy levels, and they must make ______ to transition between these levels.
The ______ states are values of energy that are permitted for electrons.
The ______ states are values of energy that are permitted for electrons.
Each ______ state can hold no more than two electrons that must have opposite spins.
Each ______ state can hold no more than two electrons that must have opposite spins.
The ______ number (n) dictates the energy level of an electron.
The ______ number (n) dictates the energy level of an electron.
The energy of a ______ increases with the value of the quantum number (l).
The energy of a ______ increases with the value of the quantum number (l).
When all the electrons occupy the lowest possible energies, an atom is said to be in its ______ state.
When all the electrons occupy the lowest possible energies, an atom is said to be in its ______ state.
The ______ configuration or structure of an atom represents the manner in which these states are occupied.
The ______ configuration or structure of an atom represents the manner in which these states are occupied.
The number of ______ in each subshell is indicated by a superscript after the shell- subshell designation in the conventional notation.
The number of ______ in each subshell is indicated by a superscript after the shell- subshell designation in the conventional notation.
______ are those that occupy the outermost shell.
______ are those that occupy the outermost shell.
The ______ classifies all elements according to their electron configuration.
The ______ classifies all elements according to their electron configuration.
The elements are situated, with increasing atomic number, in seven horizontal rows called ______.
The elements are situated, with increasing atomic number, in seven horizontal rows called ______.
All elements arrayed in a given column or group in the ______ have similar valence electron structures, as well as chemical and physical properties.
All elements arrayed in a given column or group in the ______ have similar valence electron structures, as well as chemical and physical properties.
The elements positioned in Group 0, the rightmost group, are the inert gases, which have filled ______ and stable electron configurations.
The elements positioned in Group 0, the rightmost group, are the inert gases, which have filled ______ and stable electron configurations.
Group VIIA and VIA elements are one and two ______ deficient, respectively, from having stable structures.
Group VIIA and VIA elements are one and two ______ deficient, respectively, from having stable structures.
The net force FN between two atoms is the sum of both attractive and ______ components.
The net force FN between two atoms is the sum of both attractive and ______ components.
Sometimes it is more convenient to work with the potential ______ between two atoms instead of forces.
Sometimes it is more convenient to work with the potential ______ between two atoms instead of forces.
EN, EA, and ER represent the net, attractive, and ______ energies for two isolated and adjacent atoms.
EN, EA, and ER represent the net, attractive, and ______ energies for two isolated and adjacent atoms.
The magnitude of bonding energy and the shape of the energy-versus-interatomic separation curve depend on the type of atomic ______.
The magnitude of bonding energy and the shape of the energy-versus-interatomic separation curve depend on the type of atomic ______.
Materials having large bonding energies typically also have high melting ______.
Materials having large bonding energies typically also have high melting ______.
The slope for a relatively stiff material at the r = r0 position on the curve will be quite ______; slopes are shallower for more flexible materials.
The slope for a relatively stiff material at the r = r0 position on the curve will be quite ______; slopes are shallower for more flexible materials.
A deep and narrow 'trough' in potential energy usually correlates with a low coefficient of thermal ______.
A deep and narrow 'trough' in potential energy usually correlates with a low coefficient of thermal ______.
Flashcards
Proton
Proton
A tiny particle found within the nucleus of an atom, carrying a positive electrical charge.
Neutron
Neutron
A subatomic particle located within the atom's nucleus, having no electrical charge.
Electron
Electron
A negatively charged particle that orbits the nucleus of an atom.
Bohr Atomic Model
Bohr Atomic Model
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Quantum Mechanics
Quantum Mechanics
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Subshell
Subshell
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Orbital
Orbital
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Angular Momentum Quantum Number (l)
Angular Momentum Quantum Number (l)
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Pauli Exclusion Principle
Pauli Exclusion Principle
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Ground State
Ground State
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Electron Configuration
Electron Configuration
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Valence Shell
Valence Shell
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Valence Electrons
Valence Electrons
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Stable Electron Configuration
Stable Electron Configuration
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Inert Gases (Noble Gases)
Inert Gases (Noble Gases)
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Periodic Table
Periodic Table
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Periods
Periods
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Groups
Groups
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Net force (FN)
Net force (FN)
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Attractive energy (EA)
Attractive energy (EA)
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Repulsive energy (ER)
Repulsive energy (ER)
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Bonding energy (E0)
Bonding energy (E0)
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Equilibrium interatomic separation (r0)
Equilibrium interatomic separation (r0)
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Lennard-Jones potential
Lennard-Jones potential
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Stiffness (or modulus of elasticity)
Stiffness (or modulus of elasticity)
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Study Notes
Atomic Structure and Interatomic Bonding
- Atoms consist of a nucleus (protons and neutrons) surrounded by electrons
- Electrons are negatively charged, protons are positively charged, and neutrons are neutral
- Protons and neutrons have similar mass, much larger than an electron's mass
- Atomic number (Z) identifies an element; it equals the number of protons or electrons in a neutral atom
- Atomic number ranges from 1 (hydrogen) to 92 (uranium) for naturally occurring elements
- Atomic mass (A) is the sum of protons and neutrons
- Isotopes are atoms of the same element with different numbers of neutrons, hence different atomic masses
- Atomic weight is the weighted average of naturally occurring isotopes' atomic masses
- Classical mechanics failed to explain electron behavior in solids, prompting the development of quantum mechanics
- The Bohr model depicts electrons orbiting the nucleus in well-defined orbits
- Quantum mechanics introduced the concept of electron energy quantization (electron energy levels)
- The wave-mechanical model describes electrons as probability distributions ("electron clouds") rather than precise orbits around the nucleus
- Quantum numbers describe the properties of electrons (size, shape, orientation)
Quantum Numbers
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Every electron in an atom is characterized by four quantum numbers
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The principal quantum number (n) describes the electron's energy level and average distance from the nucleus. Larger values mean higher energy levels and greater distance.
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The azimuthal quantum number (l) describes the shape of the electron's orbital. Values range from 0 to (n-1); s, p, d, and f correspond to l values of 0, 1, 2, and 3, respectively
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The magnetic quantum number (ml) describes the orientation of the electron's orbital in space
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The spin quantum number (ms) describes the intrinsic angular momentum of the electron, and can have the values +1/2 and -1/2. It indicates the direction of spin (up or down).
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The number of orbitals in a subshell is 2l+1
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The maximum number of electrons in a subshell is 4l+2
Electron Configurations
- Electron configurations describe how electrons fill available quantum states within atoms
- Electrons fill the lowest energy levels first ("aufbau" principle)
- Each state or orbital can accommodate maximum of two electrons (Pauli Exclusion Principle), with opposite spins
- The ground state configuration represents the lowest-energy arrangement of electrons
- Electrons in the outermost shell are valence electrons and play crucial roles in chemical bonding and chemical properties.
- Stable electron configurations resemble those of noble gases (fully filled valence electron shells)
The Periodic Table
- Elements are arranged in the periodic table based on electron configurations
- Elements in the same vertical column (group) have similar valence electron configurations, resulting in similar chemical and physical properties
- Elements in the same horizontal row (period) exhibit a gradual variation in properties as you move across the period
- The elements in Group 0 are inert (noble) gases, which are chemically unreactive due to full valence electron shells
- Elements on the right side of the periodic table tend to be more electronegative (accepting electrons); those on the left are electropositive (donating electrons)
- Valence electrons determine properties like metallic character, electronegativity, ionization energy, and electron affinity
Atomic Bonding in Solids
- Interatomic forces determine the behavior of solids
- Attractive and repulsive forces affect bonding energies, influencing material properties
- Bonding energies and the shape of the potential energy-versus-interatomic separation curve are crucial for understanding material properties including melting temperatures, thermal expansion, and mechanical strengths.
- Three types of primary interatomic bonds are ionic, covalent, and metallic
- Secondary bonding forces (van der Waals and hydrogen bonds) exist between molecules and can affect a material's properties.
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