The configuration of the potassium atom in its ground state is 1s2 2s2 2p6 3s2 3p6 4s1. Which of the following statement about potassium is true:
A. Its
n = 3 shell is completely filled
B. Its 4
s subshell is completely filled
C. Its least tightly bound electron has
l = 4
D. Its atomic number is 17
E. Its electron charge distribution is spherically symmetrical
(GR8677 #30)
Solution:
A. FALSE.
n = 3 →
l = 0, 1, 2 →
s,
p,
d subshells, but the configuration does not have
d subshells.
B. FALSE
4
s subshell → for
s subshell total electron should be 2 not 1.
C. FALSE
l = 0, 1, 2, 3, 4… correspond to
s,
p,
d,
f,
g, … subshells, but the configuration does not have
g subshells.
D. FALSE
the number of electrons in the configuration = 2+2+6+2+6+1 = 19, not 17.
E. TRUE
The single
s-orbitals (
l = 0) are shaped like spheres. For
n = 1 the sphere is "solid" (it is most dense at the center and fades exponentially outwardly), but for
n = 2 or more, each single
s-orbital is composed of spherically symmetric surfaces which are nested shells (i.e., the "wave-structure" is radial, following a sinusoidal radial component as well).
The outermost electron shell (valence shell) is
s1 with
n >1 and
l = 0 → spherically symmetric.
Also note that Potassium has one outer electron, like Hydrogen. So it will also have a spherically symmetrical charge distribution.
Answer: E
