1. Valence shell = outermost shell.
QUESTION:
What is the principal quantum number of the valence electrons of Iodine? A. 0, B. 4, C. 5. D. 43
Valence shell = outermost shell.
Valence electron = electron in the valence shell
Atomic number of I: 53 Electron configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p5
Valence shell: n=5
SCRIPT:
What is the principal quantum number of the valence electrons of iodine?
0…4…5…or 43
PAUSE
CLICK
The term valence shell means outermost shell. This is the shell whose electrons are, on average, farthest from the nucleus.
The larger the quantum number n,… the farther from the nucleus.
If we look up iodine, we’ll find that is atomic number is 43…
And its ground state electron configuration is …
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p5
Note that this is the ground state configuration; unless otherwise specified, when we talk
about an atom and their electron configuration, we are referring to its ground state configuration.
The valence shell, or outermost shell is the shell with the largest n.
Therefore, the valence shell of iodine is the fifth shell.
HIGHLIGHT 5s2 and 5p5
It has seven valence electrons --- two in the 5s subshell and 5 in the 5p subshell.
The principal quantum number n for all the valence electrons is 5.
We can actually figure out…. Rather easily…, the answer to this question by simply referring to the periodic table.
The periodic table is laid out so that the principal quantum number of the valence electrons of atoms in a given row all correspond to the row number.
In general,
For elements in row 1, the valence shell is the first shell.
CLICK For elements in row 2, the valence shell is the second shell.
CLICK For elements in row 3, the valence shell is the third shell
For elements in row 4, the valence shell is the fourth shell
CLICK For elements in row 5, the valence shell is the fifth shell
For elements in row 6, where Iodine belongs, the valence shell is the sixth shell
CLICK For elements in row 7, the valence shell is the seventh shell.
The same is true of the Lanthanides. These elements actually belong to row 7.
For elements in row 8, the valence shell is the eighth shell.
CLICK The same is true of the Actinides. These elements actually belong to row 8.
END RECORDING

2. Valence n=1
Valence n=2
Valence n=3
Valence n=5
Valence n=6
Valence n=7
Valence n=8
Valence n=7
Valence n=8

3. Video ID: © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Narrator: Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08