expected configuration for Cr is
1s2 2s2 2p6 3s2 3p6 4s2 3d4
but in real, it is
1s2 2s2 2p6 3s2 3p6 4s1 3d5
electron from 4s orbital jumps to 3d orbital to get stable configuration.
so the last electron comes in 3d orbital as filling of 3d takes place after filling of 4s orbital.
Hence,quantum numbers for last electron in Cr is :-
n = 3
l = 2
m = +2
s = +1/2
n=3 l=2 m=-1 s =-1/2
5, 2, +1, -1/2 :)
the inner energy level of an atom has a maximum # of
Cr [Ar] 4s^1 3d^5
n=4 l=2 ml= -1 ms= +1/2
Na has one valence electron i.e. 1 electron in valence(last) shell.
5, 2, +1, -1/2 :)
The first three quantum numbers (principle, angular momentum, magnetic) are all whole numbers. The last quantum number (spin) is either ½ or -½.
the inner energy level of an atom has a maximum # of
The magnetic quantum number, ml, runs from -l to +l (sorry this font is rubbish the letter l looks like a 1) where l is the azimuthal, angular momentum quantum number. The magnetic quantum number ml depends on the orbital angular momentum (azimuthal) quantum number, l, which in turn depends on the principal quantum number, n. The orbital angular momentum (azimuthal) quantum number, l, runs from 0 to (n-1) where n is the principal quantum number. l= 0 is an s orbital, l= 1 is a p subshell, l= 2 is a d subshell, l=3 is an f subshell. The magnetic quantum number, ml, runs from -l to +l (sorry this font is rubbish the letter l looks like a 1). ml "defines " the shape of the orbital and the number within the subshell. As an example for a d orbital (l=2), the values are -2, -1, 0, +1, +2, , so 5 d orbitals in total.
Cr [Ar] 4s^1 3d^5
exact, whole number amount of energy needed to move an electron to a higher energy level
It can reveal the number of valence electrons in the last shell.
n=4 l=2 ml= -1 ms= +1/2
In the periodic table of Mendeleev uranium is in the period 7 and actinides group.
Cobalt
quantum of solace
Boron - 5e-1s^2 2s^2 2p^1n= 2l= 1ml= -1 -> 1ms= -1/2 , 1/2