Question

Elements X, Y and Z have atomic numbers 6, 9 and 12 respectively. Which one of the given element forms an anion and cation respectively?

• A. X, Y
• B. Y, Z
• C. Z, Z
• D. X, Z

Answer 1

The correct option is B

Y, Z

Part 1: Explanation for the correct option

Option B is the correct

1. Ions are atoms or molecules that have gained or lost one or more valence electrons, resulting in a net positive or negative charge.
2. A chemical species will have a net positive charge if it has more protons than electrons. If there are more electrons than protons, the species has a negative charge.
   Given elements: $\mathrm{X}\mathrm{Y}\mathrm{Z}$
   Atomic Number: $6912$
   Electronic Configuration: $\mathrm{X}(2,4)\mathrm{Y}(2,7)\mathrm{Z}(2,8,2)$
3. $\mathrm{X}$has $4$ electrons in the valence shell, so only sharing of the electron will be possible to complete its octet.
4. $Y(2,7)$ becomes anion by gaining one electron to complete its octet.
5. $\mathrm{Z}(2,8,2)$ becomes cation by losing two electrons from its valence shell to complete its octet.

Part 2: Explanation for incorrect options

Option A:

1. Element X cannot become a cation or anion because it has 4 electrons which can neither be released nor it can accept four electrons to complete its octet.
2. Element Y forms an anion by gaining an electron.

Option C:

1. Element Z forms a cation by losing two electrons.
2. So it cannot be both cation and anion.

Option D:

1. Element X does not become a cation or anion because it has 4 electrons which can neither be released nor it can accept four electrons to complete its octet.
2. However, element Z forms a cation.

Hence, the correct option is B. Y, Z element forms an anion and cation respectively