Chem 0960 Exam 1 (Chapters 2 and 3)
Determine the mass in grams of 6.65 × 10²¹ atoms of barium. (The mass of one mole of barium is 137.33 g.)
1.51 g
What is the energy of light that must be absorbed by a hydrogen atom to transition an electron from n = 3 to n = 6?
1.82 × 10⁻¹⁹ J
Calculate the mass, in grams, of 202 atoms of iron, Fe (1 mol of Fe has a mass of 55.85 g).
1.87 × 10⁻²⁰ g
What is the mass number of tin-120?
120
Which of the following electron configurations represent a transition metal atom?
1s²2s²2p⁶3s²3p⁶4s²3d⁷
Which of the following is the electron configuration of a neutral K atom?
1s²2s²2p⁶3s²3p⁶4s¹
What is the maximum number of electrons that can have the following set of quantum numbers? n = 2, ℓ = 1, mℓ = 1.
2 Electrons
What is the maximum number of electrons that can have the quantum numbers n = 3, ℓ = 2, mℓ = 1?
2 Electrons
Calculate the wavelength in meters of electromagnetic radiation that has a frequency of 1.09 × 10⁸ s⁻¹. (c = 3.00 X 10⁸ m/s)
2.75 m
Which element has the electron configuration 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p²?
Ge
A student draws the orbital diagram below for the 3d electrons in a V atom. What, if anything, is incorrect about the drawing?
Hund's rule states that electrons are added to the atomic orbitals with the same energy levels (degenerate orbitals) in such a way that each orbital is occupied by a single electron with the same spin (either +½ or -½) before any orbital can be occupied by two electrons. In this student's diagram, one of the orbitals has two electrons while three orbitals at equal energies contain zero electrons, which is in violation of Hund's rule.
Which electron configuration violates Hund's rule?
Hund's rule states that electrons are added to the atomic orbitals with the same energy levels (degenerate orbitals) in such a way that each orbital is occupied by a single electron with the same spin before any orbital can be occupied by two electrons. Because there are three 2p orbitals, each of the individual 2p orbitals (2px, 2py, 2pz) needs to have a single electron before any of them can have two electrons. Therefore, the electron configuration [He]2s²2px²2py², which has two electrons in the 2px and 2py orbitals, but zero electrons in the 2pz orbital, is in violation of Hund's rule.
Which element has the electron configuration 1s²2s²2p⁶3s²3p⁶4s²3d⁵?
Mn
An unknown element X has the following isotopes: ²⁵X (80.5% abundant) and ²⁷X (19.5% abundant). What is the average atomic mass in amu of X?
25.4 amu
How many protons (p) and electrons (e) are found in a Se²⁻ ion?
34P, 36E
A photon of blue light has a frequency of 7.5 × 10¹⁴ Hz. Calculate the wavelength of this photon (c = 3.00 × 10⁸ m/s) in nanometers.
4 x 10^-7
What is the atomic number for an element whose mass number is 78, which contains 30 neutrons per atom?
48
Determine the energy of a photon with a wavelength of 361 nm. (h = 6.626 × 10⁻³⁴ J • s and c = 3.00 × 10⁸ m/s)
5.51 × 10⁻¹⁹ J
There are two naturally occurring isotopes of europium, ¹⁵¹Eu (151.0 amu) and ¹⁵³Eu (153.0 amu). If the atomic mass of Eu is 151.96, what is the approximate natural abundance of ¹⁵¹Eu?
50%
An unknown element X has the following isotopes: ⁵²X (90.00% abundant), ⁴⁹X (8.00% abundant), ⁵⁰X (2.00% abundant). What is the average atomic mass in amu of X?
51.7
What is the atomic number for an element whose mass number is 138, which contains 81 neutrons per atom?
57
How many electrons can be assigned to orbitals designated by the quantum numbers n = 2, ℓ = 1?
6 Electrons
Determine the number of atoms in 71.0 grams of nickel, Ni. (The mass of one mole of nickel is 58.69 g.)
7.29 × 10²³ atoms
What is the mass number for an atom of molybdenum containing 42 protons and 54 neutrons?
96
What scientist proposed that the electron in a hydrogen atom can only have certain energies (i.e., the electron is quantized)?
Bohr
Which postulate(s) of Dalton's atomic theory of matter is/are NOT true?
Both (A) and (B) (A) Atoms of a given element are identical (B) Atoms are indestructible
Which of the following elements has the smallest first ionization energy?
Cs
Which scientist developed the nuclear model of the atom?
Ernest Rutherford
Which scientist determined the charge of the electron?
Milkan
Which of the following series of isoelectronic ions (Mg²⁺, N³⁻, F⁻, Si⁴⁺) has the ionic radii in order of largest to smallest?
N³⁻ > F⁻ > Mg²⁺ > Si⁴⁺
Which has a greater mass? (Proton or Electron)?
Proton
Which particle(s) may be found in the nucleus of an atom?
Proton and Neutron
Which two particles of the atom have nearly identical masses?
Proton and Neutron
Rank the following atoms in order of increasing first ionization energies (i.e., lowest to highest): Rb, F, Mg, B, N.
Rb < Mg < B < N < F
Which element has the ground state electron configuration [Kr]5s²4d¹⁰5p³?
Sb
Which of the following is NOT an alkali or alkaline earth element?
Sc
Which of the following elements would be chemically similar to calcium (Ca)?
Sr
Which is not one of Dalton's hypotheses of atomic theory?
The atoms of one element are the same as atoms of another element.
Which of the following series of elements has nearly the same atomic radii?
Ti, V, Cr, Mn
Which element has the ground state electron configuration [Xe]6s²4f¹⁴5d⁴?
W
Which of the following represents a species with 39 protons and 36 electrons?
Y³⁺
Halogens tend to form anions because
gaining electrons will fill their octet faster than losing them.
Rutherford's gold foil experiment determined that
most of the space in an atom is empty except for a concentrated area called the nucleus.
A single electron in an orbital has quantum numbers n = 2, ℓ = 0, mℓ = 0, ms = +½. What are the quantum numbers for the next electron added to this atom?
n = 2, ℓ = 0, mℓ = 0, ms = -½
The nucleus of an atom contains:
protons and neutrons
Which of the following pairs represent isotopes?
²⁸Si and ²⁹Si
