Question

Which of the following species has the greatest

Answer 1

Among the given species, $\boxed{3.{\text{ F}}{{\text{e}}^{2 + }}}$ has the greatest number of electrons.

Further Explanation:

The arrangement of electrons in various shells and sub-shells of an atom is called electronic distribution. The electron filling is done by keeping following rules and principles in mind:

(i). Aufbau principle

According to this, electron filling takes place in orbitals in the increasing order of their respective energies. The energy order of orbitals is as follows:

$1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s < 4f < 5d < 6p < 7s < 5f < 6d < 7p$

 

(ii) Hund’s rule

No electron will b epaired until each orbital is singly occupied.

(iii) Pauli’s exclusion principle

It states that two electrons can never have all the four quantum numbers same. The value of spin quantum number for both electrons must b edifferent.

1. According to the periodic table, the atomic number of Cl is 17 so its electronic configuration is $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^7}4{s^2}$. It gains an electron to form ${\text{C}}{{\text{o}}^{4 + }}$ ion and its configuration becomes $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^5}$. So it has a total of 18 electrons.

2. According to the periodic table, the atomic number of Co is 27 so its electronic configuration is $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^7}4{s^2}$. It loses four electrons, two 4s electrons and two 3d electrons to form   ion and its configuration becomes $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^5}$. So it has a total of 23 electrons.

3. According to the periodic table, the atomic number of Fe is 26 so its electronic configuration is $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^6}4{s^2}$. It loses two 4s electrons to form ${\text{F}}{{\text{e}}^{2 + }}$ ion and its configuration becomes $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^6}$. So it has a total of 24 electrons.

4. According to the periodic table, the atomic number of V is 23 so its electronic configuration is $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^3}4{s^2}$. So it has a total of 23 electrons.

5. According to the periodic table, the atomic number of Sc is 21 so its electronic configuration is $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^1}4{s^2}$. It gains two electrons to form ${\text{S}}{{\text{c}}^{2 - }}$ ion and its configuration becomes $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^3}4{s^2}$. So it has a total of 23 electrons.

Therefore, the maximum number of electrons is present in ${\text{F}}{{\text{e}}^{2 + }}$ (24).

Learn more:

1. Determine the ion with configuration  : brainly.com/question/7599542
2. Identification of element which has electron configuration  :brainly.com/question/9616334

Answer details:

Grade: High School

Chapter: Electronic configuration of the elements

Subject: Chemistry

Keywords: electrons, Cl-, Co4+, Fe2+, V, Sc2-, 17, 27, 26, 21, 23, electronic configuration.

Answer 2

Answer: Option (3) is the correct answer.

Explanation:

When there is a negative charge on an atom then we add the charge with the number of electrons. Whereas when there is a positive charge on an atom then we subtract the charge from the number of electrons.

Atomic number of chlorine is 17. So, number of electrons present in $Cl^{-}$ is 17 + 1 = 18 electrons.

Atomic number of cobalt is 27. So, number of electrons present in $Co^{4+}$ is 27 - 4 = 23 electrons.

Atomic number of iron is 26. So, number of electrons present in $Fe^{2+}$ is 26 - 2 = 24 electrons.

Atomic number of vanadium is 23. So, number of electrons present in V is 23 electrons.

Atomic number of scandium is 21. So, number of electrons present in $Sc^{2-}$ is 21 + 2 = 23 electrons.

Thus, we can conclude that out of the given species, $Fe^{2+}$ has the greatest  number of electrons.