CHEM Structure of the Atom

Which of the following elements has teh greatest number of p electrons? (a) As (b) Si (c) Fe (d) Cl

(a) As Arsenic has a total of 15 p electrons: 6 in period 2, 6 in period 3, and 3 in period 4.

Which of the following principles is NOT part of Dalton's atomic theory? (a) Chemical reactions are simple rearrangements of atoms. (b) Atoms follow the law of multiple proportions. (c) Each atom of an element is identical to every other atom of that element. (d) All matter is composed of atoms.

(b) Atoms follow the law of multiple proportions. The law of multiple proportions is a consequence of the atomic theory, not part of it.

An electron with the four quantum numbers 3, 2, -1, -1/2 may be an electron in an unfilled sublevel of (a) Ca (b) Fe (c) Al (d) Ag

(b) Fe These quantum numbers represent a 3d electron (the second quantum number is 2) in the third energy level (the first quantum number is 3). Only Fe has an incompletely filled d sublevel.

Which quantum number describes the shape of an orbital? (a) n (b) l (c) ml (d) ms

(b) l The l or second quantum number defines orbital shape.

Which of these will tell you the shape of any orbital that an electron may occupy? (a) n (b) s (c) ml (d) ms

(c) The quantum number ml indicates the shape of the orbital.

The best tool to use to calculate the ionization energy of a hydrogen atom is (a) Rydberg equation (b) Heisenberg uncertainty principle (c) Hund's rule (d) Pauli exclusion principle

(a) Rydberg equation The Rydberg equation, if the larger value of n is set to an infinitely large number (indicating complete removal of the electron) can easily provide this answer.

Which of the following is FALSE? (a) The 4d orbitals are in the fourth period of the periodic table. (b) The 7s orbitals are in the seventh period of the periodic table. (c) The 4f orbitals are in the sixth period of the periodic table. (d) The 6s orbitals are spherical in shape.

(a) The 4d orbitals are in the fourth period of the periodic table. The 4 d electrons appear in the fifth period of the periodic table.

Which electronic transition requires the addition of the most energy? (a) n = 1 to n = 3 (b) n = 5 to n = 2 (c) n = 2 to n = 3 (d) n = 4 to n = 1

(a) n = 1 to n = 3 Energy is needed to increase the value of n, and energy is released when n decreases. The more levels by which the electron increases, the greater the energy needed.

The f sublevel may contain a maximum of (a) 2 electrons. (b) 14 electrons. (c) 6 electrons. (d) 10 electrons.

(b) 14 electrons. The f orbitals in the sixth and seventh periods hold 14 electrons.

Our inability to know precisely the position and momentum of a subparticle is summarized by (a) Rydberg equation (b) Heisenberg uncertainty principle (c) Hund's rule (d) Pauli exclusion principle

(b) Heisenberg uncertainty principle The Heisenberg uncertainty principle says that the more precisely we know the position, the less precisely we know its momentum, and vice versa.

The designation for an electron in calcium can occur only if calcium is in an excited state. (a) n and s (b) f (c) n, s, and ml (d) ml and ms

(b) f On s and f represent orbitals. Calcium can have s orbitals filled while in the ground state. It has no f orbitals and the only way this could have an electron is in the excited state.

Which of these symbols represents an orbital? (a) n and s (b) s and f (c) n, s, and f (d) ml and ms

(b) s and f The s and f represent orbitals, while the other symbols represent quantum numbers.

Which electronic configuration corresponds to that of a noble gas? (a) 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 (b) 1s^2 2s^2 2p^6 3s^2 3p^4 (c) 1s^2 2s^2 2p^6 3s^2 3p^6 (d) 1s^2 2s^2 2p^6 3s^1

(c) 1s^2 2s^2 2p^6 3s^2 3p^6 The electronic configuration of a noble gas always ends with np^6. These gases also have an ns^2 in their structure, where n is the highest principal level.

What is the wavelength of light that has a frequency of 4.00 x 10^14 (1/s)? The speed of light is 3.00 x 10^8 m/s. (a) 7.5 nm (b) 1333 nm (c) 750 nm (d) 1.33 cm^-1

(c) 750 nm Solve the equation (wavelength)(v) = c. wavelength = 3.00 x 10^8 ms^-1 / 4.00 x 10^14 s^-1 = 7.5 x 10^-7 m = 750 nm

Which element has an electronic configuration that does NOT follow the Aufbau principle? (a) Fe (b) Al (c) Ag (d) Ni

(c) Ag An element that has an initial d^4 and d^9 electron configuration is usually going to promote an s electron to give a d^5 or d^10 configuration, which is more stable. Ag is one of those elements.

In filling the atom with electrons, the rule(s) that must be considered are (a) Rydberg equation and Hund's rule (b) Hund's rule (c) Hund's rule and Pauli exclusion principle (d) Pauli exclusion principle

(c) Hund's rule and Pauli exclusion principle Hund's rule says that all orbitals at a given energy level are filled with one electron each before pairing occurs. The Pauli exlusion principle means that no two electrons can have all four quantum numbers the same or two unpaired electrons cannot share an orbital.

Which was used to determine the charge of the electron? (a) The gold foil experiment (b) Deflection of cathode rays by electric and magnetic fields (c) The oil drop experiment (d) The mass spectrometer

(c) The oil drop experiment The Millikan oil-drop experiment determined the charge of the electron independent of the mass.

The valence electrons are (a) all electrons in an atom beyond the preceding noble gas. (b) all outermost electrons in a sublevel. (c) s and any p electrons in the highest energy level or shell. (d) electrons in the last unfilled sublevel.

(c) s and any p electrons in the highest energy level or shell. Valence electrons are the electrons in the outermost energy level of the atom. Only the s and p electrons are in the same energy level as the period in the periodic table.

The numbers of electrons, protons, and neutrons, respectively, in the 31P isotope are (a) 15, 31, 15 (b) 15, 15, 31 (c) 31, 15, 16 (d) 15, 15, 16

(d) 15, 15, 16 A = 31 and Z = 15. In a neutral atom the electrons and protons are each equal to Z. The differences between A and Z is the number of neutrons = 16.

You have just discovered a new, fundamental particle of nature. When measuring its mass, you obtain the following data for five samples: 4.72 x 10^-34 gram 9.44 x 10^-34 gram 1.18 x 10^-33 gram 1.65 x 10^-33 gram (a) 4.72 x 10^-34 gram (b) 1.18 x 10^-34 gram (c) 9.44 x 10^-34 gram (d) 2.36 x 10^-34 gram

(d) 2.36 x 10^-34 gram 2.36 x 10^-34 is the largest common divisor of all five measurements.

Which equation best expresses the energy of a photon? (a) E = 1/2 mv^2 (b) E = mc^2 (c) E = IR (d) E = hv

(d) E = hv E = hv is the equation for determining the energy of a photon.

Which of the following atoms has the most unpaired electrons? (a) Mg (b) Ti (c) Al (d) Fe

(d) Fe Iron has an electron configuration of [Fe] 4s^2 3d^6, giving it four unpaired electrons.

Which of the following has only five valence electrons? (a) RB (b) C (c) Si (d) P

(d) P Phosphorus is in Group VA and has five valence electrons.

Bohr's equation for the energy of an electron in its orbit can be used (a) to calculate the energy released as an electron drops from a high orbit to a lower one. (b) to determine the energy needed to promote an electron to a higher energy level. (c) to understand the spectra of the hydrogen atom. (d) for all of the above purposes.

(d) for all of the above purposes. Bohr's model of the atom demonstrated that the Rydberg equation could be used for all of the listed purposes.

For a d orbital: (a) the value of n must be 2 (b) the value of ms must be +1/2 (c) the value of l must be 3 (d) the value of l must be 2

(d) the value of l must be 2 When l = 0 it si an s orbital; l = 1, a p orbital; l = 2, a d orbital.

Which of the following types of electromagnetic radiation has the highest energy? (a) visible (b) ultraviolet (c) infrared (d) x-rays

(d) x-rays The order of energies is as follows: microwave < infrared < visible < ultraviolet < x-rays.