Since Kr or Krypton is a noble gas, it has a full valence shell or octet of 8 electrons. If this helped, leave a like:). Diagram of the nuclear composition, electron configuration, chemical data, and valence orbitals of an atom of krypton (atomic number: 36), the most common. Box spin diagram of outer electron orbitals for the electron configuration of the atom. 36 Krypton, Kr, Ar3ds24p6 = Kr , Ar3d 4s 4p v. 2021: Valence Electrons in Krypton (Kr) & Facts, Color, Discovery. A valence electron is an outer shell electron and may participate in the formation of a chemical bond. Ok but how many valence electrons does an atom of Krypton have? In the case of Krypton the valence electrons is 0. Naturally occurring krypton in Earth's atmosphere is composed of five stable isotopes, plus one isotope (78 Kr) with such a long half-life (9.2×10 21 years) that it can be considered stable. (This isotope has the second-longest known half-life among all isotopes for which decay has been observed; it undergoes double electron capture to 78 Se). Give the correct number of valence electrons for the element krypton, Kr, atomic #36. Check Give the correct number of valence electrons for the element gallium, Ga, atomic #31.
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First: Determine the number of electrons. Krypton has a total of 36 electrons
Second: KNOW YOUR ORBITALS
Know how many electrons each orbital can hold and their order.
(Refer to the following pictures as notes)
Third: Write out the electron configuration
For Krypton and most of the elements there are more the just one way (usually two) to write the electron configuration. One way is to write out the entire electron configuration by going through each orbital or we can use a shorthand notation using the noble gases as a starting point. I will go through both methods:
First Method: (Long way)
We know that Krypton has
We know that the
Second Method (Shorthand)
The key to using this method is to identify the noble gas closest to the desired element that is at a lower energy (Has a lower atomic number if I'm loosely speaking). In essence, the shorthand notation tells us the configuration by using a noble gas element as our starting point instead of starting all the way at the
Coincidently, Krypton itself is a noble gas so we could write the electron configuration as
*Notice how the configuration
All in all, the three given answers are correct ways of figuring out the ground-state electron configuration of Krypton .
Contents:
Quantum Numbers and Atomic Orbitals
1. Principal Quantum Number (n)
2.Angular Momentum (Secondary, Azimunthal) Quantum Number (l)
3.Magnetic Quantum Number (ml)
4.Spin Quantum Number (ms)
Table of Allowed Quantum Numbers
Writing Electron Configurations
Properties of Monatomic Ions
References
By solving the Schrödinger equation (Hy = Ey), we obtain a set of mathematical equations, called wave functions (y), which describe the probability of finding electrons at certain energy levels within an atom.
A wave function for an electron in an atom is called an atomic orbital; this atomic orbital describes a region of space in which there is a high probability of finding the electron. Energy changes within an atom are the result of an electron changing from a wave pattern with one energy to a wave pattern with a different energy (usually accompanied by the absorption or emission of a photon of light).
Each electron in an atom is described by four different quantum numbers. The first three (n, l, ml) specify the particular orbital of interest, and the fourth (ms) specifies how many electrons can occupy that orbital.
l | 0 | 1 | 2 | 3 | 4 | 5 | ... |
Letter | s | p | d | f | g | h | ... |
The subshell with n=2 and l=1 is the 2p subshell; if n=3 and l=0, it is the 3s subshell, and so on. The value of l also has a slight effect on the energy of the subshell; the energy of the subshell increases with l (s < p < d < f).
n | l | ml | Number of orbitals | Orbital Name | Number of electrons |
1 | 0 | 0 | 1 | 1s | 2 |
2 | 0 | 0 | 1 | 2s | 2 |
1 | -1, 0, +1 | 3 | 2p | 6 | |
3 | 0 | 0 | 1 | 3s | 2 |
1 | -1, 0, +1 | 3 | 3p | 6 | |
2 | -2, -1, 0, +1, +2 | 5 | 3d | 10 | |
4 | 0 | 0 | 1 | 4s | 2 |
1 | -1, 0, +1 | 3 | 4p | 6 | |
2 | -2, -1, 0, +1, +2 | 5 | 4d | 10 | |
3 | -3, -2, -1, 0, +1, +2, +3 | 7 | 4f | 14 |
The distribution of electrons among the orbitals of an atom is called the electron configuration. The electrons are filled in according to a scheme known as the Aufbau principle ('building-up'), which corresponds (for the most part) to increasing energy of the subshells:
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f
It is not necessary to memorize this listing, because the order in which the electrons are filled in can be read from the periodic table in the following fashion:
Or, to summarize:
In electron configurations, write in the orbitals that are occupied by electrons, followed by a superscript to indicate how many electrons are in the set of orbitals (e.g., H 1s1)
Another way to indicate the placement of electrons is an orbital diagram, in which each orbital is represented by a square (or circle), and the electrons as arrows pointing up or down (indicating the electron spin). When electrons are placed in a set of orbitals of equal energy, they are spread out as much as possible to give as few paired electrons as possible (Hund's rule).
examples will be added at a later date
In a ground state configuration, all of the electrons are in as low an energy level as it is possible for them to be. When an electron absorbs energy, it occupies a higher energy orbital, and is said to be in an excited state.
The electrons in the outermost shell (the ones with the highest value of n) are the most energetic, and are the ones which are exposed to other atoms. This shell is known as the valence shell. The inner, core electrons (inner shell) do not usually play a role in chemical bonding.
Elements with similar properties generally have similar outer shell configurations. For instance, we already know that the alkali metals (Group I) always form ions with a +1 charge; the 'extra' s1 electron is the one that's lost:
IA | Li | 1s22s1 | Li+ | 1s2 |
Na | 1s22s22p63s1 | Na+ | 1s22s22p6 | |
K | 1s22s22p63s23p64s1 | K+ | 1s22s22p63s23p6 |
The next shell down is now the outermost shell, which is now full — meaning there is very little tendency to gain or lose more electrons. The ion's electron configuration is the same as the nearest noble gas — the ion is said to be isoelectronic with the nearest noble gas. Atoms 'prefer' to have a filled outermost shell because this is more electronically stable.
IIA | Be | 1s22s2 | Be2+ | 1s2 |
Mg | 1s22s22p63s2 | Mg2+ | 1s22s22p6 | |
IIIA | Al | 1s22s22p63s23p1 | Al3+ | 1s22s22p6 |
IVA | Sn | [Kr]4d105s25p2 | Sn2+ | [Kr]4d105s2 |
Sn4+ | [Kr]4d10 | |||
Pb | [Xe]4f145d106s26p2 | Pb2+ | [Xe]4f145d106s2 | |
Pb4+ | [Xe]4f145d10 | |||
VA | Bi | [Xe]4f145d106s26p3 | Bi3+ | [Xe]4f145d106s2 |
Bi5+ | [Xe]4f145d10 |
IVA | C | 1s22s22p2 | C4- | 1s22s22p6 |
VA | N | 1s22s22p3 | N3- | 1s22s22p6 |
VIA | O | 1s22s22p4 | O2- | 1s22s22p6 |
VIIA | F | 1s22s22p5 | F- | 1s22s22p6 |
B-group | Fe | 1s22s22p63s23p63d64s2 | Fe2+ | 1s22s22p63s23p63d6 |
Fe3+ | 1s22s22p63s23p63d5 |
Martin S. Silberberg, Chemistry: The Molecular Nature of Matter and Change, 2nd ed. Boston: McGraw-Hill, 2000, p. 277-284, 293-307.