- The four quantum numbers (n, l, ml,and ms) that describe the valence electron in the
cesium atom are
A. 6, 0, −1, +1/2
B. 6, 1, 1, +1/2
C. 6, 0, 0, +1/2
D. 6, 1, 0, +1/2
E. 6, 0, 1, −1/2Answer: C
The valence electron for the cesium atom is in the 6s orbital. In assigning quantum numbers,
n= principal energy level = 6. The quantum number lrepresents the angular momentum (type
of orbital) with sorbitals = 0, porbitals = 1, dorbitals = 2, and so forth. In this case, l= 0. The
quantum number mlis known as the magnetic quantum number and describes the orientation of
the orbital in space. For sorbitals (as in this case), mlalways equals 0. For porbitals, mlcan
take on the values of −1, 0, and +1. For dorbitals, mlcan take on the values −2, −1, 0, +1,
and +2. The quantum number msis known as the electron spin quantum number and can take
only two values, +1/2 and −1/2, depending on the spin of the electron.
- When subjected to the flame test, a solution that contains K+ions produces the color
A. yellow
B. violet
C. crimson
D. green
E. orangeAnswer: B
Refer to Key Concepts for colors of flame tests.
10. Which of the following results indicates exothermic change in atoms?A. The production of line emission spectra
B. The appearance of dark lines in absorption spectra
C. The formation of ions from a metal in the gaseous state
D. The production of isotopic species of CO+and CO 2 +when CO 2 is placed in a mass
spectrometer
E. The absence of all spectral lines in the region of excitationElectronic Structure of Atoms