^A_ZX

What are A, Z, and X?

A = atomic mass number (P + N)
Z = atomic number (P) 

X = chemical symbol

^131m₅₄Xe

What does 'm' stand for?

Metastable state

Ex: ^131m₅₄Xe is an isomer of ^131₅₄Xe.

A. How many stable nuclei exist?
B. What percentage of stable nuclei are even-even nuclei?
C. What percentage have even Z, odd N?

D. What percentage have odd Z, even N?

E. How many odd-odd nuclei are stable? What are they? 

A. ~300
B. >50%

C. ~20%

D. ~20%

E. 4 (²₁H , ⁶₃Li , ¹⁰₅B , ¹⁴₇N)

A. What does 'amu' stand for?

B. What is the traditional definition of 1 amu?

C. 1 amu = _______ kg?
D. A mass expressed in amu is also known as what? (2 answers) 

A. amu = atomic mass unit

B. 1 amu is equal to the 1/12 the mass of a ¹²₆C atom

C. 1 amu = 1.66 x 10^-27 kg

D. atomic mass or atomic weight

The mass of a substance in grams equal to the atomic weight of that substance

Ex: The gram-atomic weight of ¹²₆C is 12g.

A. What does Avogadro's law state?

B. What is the symbol for Avogadro's Number?
C. What does Avogadro's Number equal? 

A. Avogadro's law states that the gram-atomic weight of any atom (subatomic particle, molecule, etc.) contains the same number of atoms, and that number is Avogadro's Number.

B. N_A

C. N^A = 6.0228 x 10²³

A. Electron = ______ amu

B. Proton = ______ amu

C. Neutron = ______ amu

A. Electron = 0.000548 amu

B. Proton = 1.00727 amu

C. Neutron = 1.00866 amu

A. Why does the mass of an atom not equal the sum of the masses of its constituents?

B. What is this difference in mass called? (2 answers)

A. The mass of an atom does not equal the sum of the masses of its constituents because a certain mass is converted into energy that acts as the "glue" that holds the constituents together.

B. This is known as the mass defect or the binding energy of the nucleus.

A. Joule, J

B. A joule is defined as the work done when a force of 1N (1N = 1kg*m/s²) acts through a distance of 1 m.

1J = 1N*m = 1kg*m²/s²

A. What is an electron-volt, eV?

B. 1 ev = ______ J 

A. An eV is the kinetic energy acquired by an electron as it passes through a potential difference of 1V.

B. 1 eV = 1V x 1.602 x 10^-19C = 1.602 x 10^-19J

A. What is the symbol for the speed of light?

B. What is the speed of light in m/s?

A. Speed of light, c

B. c = 2.998 x 10⁸ m/s

A. Einstein's Principle of Mass and Energy states that mass and energy are interconvertible.

B. E = mc²

A. Energy equivalent, E₀

B. 1 amu = 931 MeV

A. What is the mass of an electron (m_e) in kg?

B. What is the energy equivalent of an electron at rest?

A. m_e = 9.1 x 10^-31 kg

B. E_0,e^- = 0.511 MeV

Masses of particles can also be expressed in GeV/c².

1 GeV/c² = _____ amu

A. In 1913, Neils Bohr proposed an atomic model.  Describe this model.

B. This model is essentially a quantum interpretation of what pre-existing atomic model?

A. Electrons revolve around the nucleus of an atom in definite orbits (corresponding to definite energy levels) and are prevented from leaving the atom by the centripetal force of attraction between the positively charged nucleus and the negatively charged electrons.

B. The Rutherford model, proposed in 1911 by Ernest Rutherford.

A. What is Planck's constant?

B. What is the symbol for Planck's constant?
C. What is Planck's constant equal to? 

A. Planck's constant describes the sizes of 'quanta' in quantum mechanics.

B. Planck's constant, h

C. h = 6.626 x 10^-34 J*s

A. What formula determines the maximum number of electrons in a particular shell?

B. Give the symbol and maximum number of orbital electrons for each shell (n = 1-5) 

A. 2n²

B. (1) K, 2 electrons

(2) L, 8 electrons

(3) M, 18 electrons

(4) N, 32 electrons

(5) O, 50 electrons

Electronic orbits can also be considered energy levels.

A. What is the corresponding energy?

B. With an opposite sign, this energy is equal to ______.

A. The energy level of an atomic orbit corresponds to that electron's potential energy.

B. With an opposite sign, the potential energy of an orbital electron is equal to the binding energy, E_B, of that electron.

[image]

What is this type of diagram called?

Increase. 

Binding energy is proportional to the coulombic force of attraction between the nucleus and the electron.  As Z increases, so does the magnitude of the nucleus' positive charge.

A. The outer shell

B. Valence electrons

A. Describe the process of optical radiation.  

B. Which electrons are involved in the emission of optical radiation?

A. Optical radiation occurs when an orbital electron is excited (gains energy).  This excited electron is unstable, and as it falls back to its ground state, a photon of energy equal to the energy difference between the states is emitted.

B. Valence electrons are typically associated with optical radiation.

A. When are characteristic x-rays given off?

B. Why are these x-rays 'characteristic'?

A. Characteristic x-rays are given off when an ejected inner-shell electron is replaced by an electron from an outer shell.  When the replacing electron falls to an inner shell, a photon of energy equal to the difference between the binding energies of the shells is emitted.  

B. These photons are 'characteristic' because the binding energies of electrons orbiting a particular nuclide are characteristic of that nuclide.  Thus, the characteristic x-rays emitted from a nuclide exist in only a small number of energies.

1. Strong Nuclear Force

2. Electromagnetic Force

3. Weak Nuclear Force
4. Gravitational Force 

A. What is wave-particle duality?

B. What physicist proposed the idea, and in what year?

A. Wave-particle duality says that electromagnetic waves can behave like particles (i.e. exhibit momentum).  A discrete electromagnetic wave behaving like a particle is called a photon.  Conversely, particles sometimes act like waves (i.e. exhibit refraction).

B. Wave-particle duality was proposed by Louis de Broglie in 1925.

Fermions- constituents of matter

Bosons- force carriers

c = νλ

c, speed of light = 2.998 x 10⁸ m/s

ν, frequency (s^-1, hertz)

λ, wavelength (m)

To explain certain phenomena, such as the photoelectric effect and compton scattering, one must consider the electromagnetic wave to be particulate.  

What formula describes a photon?

E = hν

E, energy

h, Planck's constant = 6.626 x 10^-34 J*s

ν, frequency (s^-1, hertz)

A. In 1897, British physicist Sir J.J. Thomson proposed an atomic model.  Briefly describe his theory.

B. This model is often referred to as ______.

A. Thomson proposed that the atom consisted of electrons moving in constant motion inside a positively-charged medium.

B. the plum pudding model.

Quantum Mechanics Principles

A. Are the energy levels of orbital electrons discrete or continuous?

B. How are all orbital electrons defined?

C. In a single atom, no two electrons _______.

D. Name three of the physicists who independently proposed these principles.

A. discrete

B. All orbital electrons are defined by a set of quantum numbers (n, l, m_l, m_s).

C. ...can have the same set of quantum numbers.  This is known as the Pauli exclusion principle (Wolfgang Pauli, 1925).

D.

(1) Wolfgang Pauli
(2) Erwin Schrodinger

(3) Werner Heisenberg 

(1) Principle quantum number, n

Corresponds to the shell (K=1, L=2, etc)

1 < n < 6

(2) Orbital quantum number, l

Corresponds to the subshell (s=0, p=1, d=2, f=3, g=4)

0 < l < n-1

(3) Magnetic quantum number, m_l

Corresponds to the specific orbit within the subshell

-l < m_l < l

(4) Spin quantum number, m_s

Corresponds to the spin of the electron

s = 1/2 (clockwise) , -1/2 (counter-clockwise)

A. Sort the following types of electromagnetic waves in order of increasing frequency:

infrared, microwaves, radar, radio, tv, ultraviolet, visible light, x-rays

B. What wavelengths correspond to the range of visible light?

A.

(1) radio

(2) tv
(3) radar
(4) microwaves

(5) infrared

(6) visible light

(7) ultraviolet

(8) x-rays

B. 4 x 10^-7m (Blue) --> 7 x 10^-7m (Red)