Respuesta :
Answer: [tex]Kr=Ar>Br=Cl=Fl>O>As=Sb>Si>Al>Ca=Ba=Sr>Li=Na[/tex]
Explanation: Valence electrons are defined as the outermost electrons present in an atom that are easy to loose. It can be easily recognized from the electronic configuration.
- Electronic configuration of [tex]Kr:[Ar]4s^24p^6[/tex], Number of valence electrons = 8
- Electronic configuration of [tex]Ca:[Ar]4s^2[/tex], Number of valence electrons = 2
- Electronic configuration of [tex]Ba:[Xe]6s^2[/tex], Number of valence electrons = 2
- Electronic configuration of [tex]Br:[Ar]4s^24p^5[/tex], Number of valence electrons = 7
- Electronic configuration of [tex]Li:[He]2s^1[/tex], Number of valence electrons = 1
- Electronic configuration of [tex]F:[He]2s^22p^5[/tex], Number of valence electrons = 7
- Electronic configuration of [tex]As:[Ar]4s^24p^3[/tex], Number of valence electrons = 5
- Electronic configuration of [tex]Sb:[Kr]5s^25p^3[/tex], Number of valence electrons = 5
- Electronic configuration of [tex]O:[He]2s^22p^4[/tex], Number of valence electrons = 6
- Electronic configuration of [tex]Al:[Ne]3s^23p^1[/tex], Number of valence electrons = 3
- Electronic configuration of [tex]Cl:[Ne]3s^23p^5[/tex], Number of valence electrons = 7
- Electronic configuration of [tex]Si:[Ne]3s^23p^2[/tex], Number of valence electrons = 4
- Electronic configuration of [tex]Na:[Ne]3s^1[/tex], Number of valence electrons = 1
- Electronic configuration of [tex]Ar:[Ne]3s^23p^6[/tex], Number of valence electrons = 8
- Electronic configuration of [tex]Sr:[Kr]5s^2[/tex], Number of valence electrons = 2
Elements arranged in decreasing order of their valence electrons are: [tex]Kr=Ar>Br=Cl=Fl>O>As=Sb>Si>Al>Ca=Ba=Sr>Li=Na[/tex]
The decreasing order of elements of the number of valence electrons is as follows:
[tex]\boxed{{\text{Kr}}={\text{Ar}}>{\text{Br}}={\text{Cl}}={\text{F}}>{\text{O}}>{\text{As}}={\text{Sb}}>{\text{Si}}>{\text{Al}}>{\text{Ca}}={\text{Ba}}={\text{Sr}}>{\text{Li}}>{\text{Na}}}[/tex]
Further explanation:
The electronic configuration is the distribution of electrons of an atom in the atomic orbitals. There are two states for an electron: ground as well as the excited state. The configuration of the atom in the lowest possible energy levels is called the ground-state electronic configuration. When an electron jumps from the stable ground state to some higher level, that state is called the excited state and the electronic configuration corresponding to this state is known as the excited-state half-filled configuration.
The filling of electrons in different energy levels or orbitals is done in accordance with the following three rules.
1. Aufbau principle: The principle states that the electrons are filled in various orbitals in the increasing order of their energies as follows:
[tex]1s<2s<2p<3s<3p<4s<3d<4p<5s<4d<5p<6s<4f<5d<6p<7s<5f<6d<7p[/tex]
2. Hund’s rule: Electron pairing will not start until each orbital is singly occupied.
3. Pauli’s exclusion principle: According to this principle, all the four quantum numbers [tex]\left({n,\;l,\;{m_l},\;{m_s}}\right)[/tex] for any two electrons can never be the same. In an orbital, the spin of two electrons has to be different. If one electron has the clockwise spin, the other would have the anticlockwise spin and vice-versa.
The atomic number of Kr is 36. Its electronic configuration is [tex]\left[{{\text{Ar}}}\right]\;3{d^{10}}4{s^2}4{p^6}[/tex]. So it has 8 valence electrons.
The atomic number of Ca is 20. Its electronic configuration is [tex]\left[{{\text{Ar}}}\right]4{s^2}[/tex]. So it has 2 valence electrons.
The atomic number of Ba is 56. Its electronic configuration is [tex]\left[{{\text{Xe}}}\right]6{s^2}[/tex]. So it has 2 valence electrons.
The atomic number of Br is 35. Its electronic configuration is [tex]\left[{{\text{Ar}}}\right]\;3{d^{10}}4{s^2}4{p^5}[/tex]. So it has 7 valence electrons.
The atomic number of Li is 3. Its electronic configuration is [tex]1{s^2}2{s^1}[/tex]. So it has 1 valence electron.
The atomic number of F is 9. Its electronic configuration is [tex]\left[{{\text{He}}}\right]\;2{s^2}2{p^5}[/tex]. So it has 7 valence electrons.
The atomic number of As is 33. Its electronic configuration is [tex]\left[{{\text{Ar}}}\right]\;3{d^{10}}4{s^2}4{p^3}[/tex]. So it has 5 valence electrons.
The atomic number of Sb is 51. Its electronic configuration is [tex]\left[{{\text{Kr}}}\right]\;4{d^{10}}5{s^2}5{p^3}[/tex]. So it has 5 valence electrons.
The atomic number of O is 8. Its electronic configuration is [tex]\left[{{\text{He}}}\right]\;2{s^2}2{p^4}[/tex]. So it has 6 valence electrons.
The atomic number of Al is 13. Its electronic configuration is [tex]\left[{{\text{Ne}}}\right]\;3{s^2}3{p^1}[/tex]. So it has 3 valence electrons.
The atomic number of Cl is 17. Its electronic configuration is [tex]\left[{{\text{Ne}}}\right]\;3{s^2}3{p^5}[/tex]. So it has 7 valence electrons.
The atomic number of Si is 14. Its electronic configuration is [tex]\left[{{\text{Ne}}}\right]\;3{s^2}3{p^2}[/tex]. So it has 7 valence electrons.
The atomic number of Na is 11. Its electronic configuration is [tex]\left[{{\text{Ne}}}\right]\;3{s^1}[/tex]. So it has 1 valence electron.
The atomic number of Ar is 18. Its electronic configuration is [tex]\left[{{\text{Ne}}}\right]\;3{s^2}3{p^6}[/tex]. So it has 8 valence electrons.
The atomic number of Sr is 38. Its electronic configuration is [tex]\left[{{\text{Kr}}}\right]\;5{s^2}[/tex]. So it has 2 valence electrons.
So the decreasing order of elements of the number of valence electrons is as follows:
[tex]{\text{Kr}}={\text{Ar}}>{\text{Br}}={\text{Cl}}={\text{F}}>{\text{O}}>{\text{As}}={\text{Sb}}>{\text{Si}}>{\text{Al}}>{\text{Ca}}={\text{Ba}}={\text{Sr}}>{\text{Li}}>{\text{Na}}[/tex]
Learn more:
1. Determine the ion with configuration [tex]\left[{{\text{Ar}}}\right]\;3{d^2}[/tex]: https://brainly.com/question/7599542
2. Identification of element which has electron configuration [tex]1{s^2}2{s^2}2{p^2}3{s^1}[/tex]:https://brainly.com/question/9616334
Answer details:
Grade: High School
Subject: Chemistry
Chapter: Electronic configuration of the elements
Keywords: electronic configuration, valence electrons, decreasing order, Kr, Ar, Cl, Br, F, O, As, Sb, Si, Al, Ca, Ba, Sr, Li, Na, 8, 7, 6, 5, 4, 3, 2, 1, Aufbau, Hund’s rule, Pauli’s exclusion principle.
