Question

Give an example of the species that has a linear shape

Answer 1

VSEPR theory:

1. The Valence Shell Electron Pair Theory (VSEPR theory) helps in determining the molecule's geometry and shape.
2. It is based on the observation that all atoms' valence electron pairs repel one another and that the atoms organize themselves in such a way that this repulsion is minimized in the resulting geometry.

Example:

1. In ${\mathrm{BeCl}}_2$, Beryllium is bounded to two Chlorine atoms.
2. Electronic configuration of beryllium with atomic number $4$is $1{\mathrm{s}}^{2}2{\mathrm{s}}^2$. Number of valence electron$=2$
3. Electronic configuration of Chlorine with atomic number $17$ is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^5$. Number of valence electron$=7$
4. Two chlorine atoms get attached to beryllium to complete their octet and leave no lone pair of electrons.
5. Two electron pairs exist, and in order to reduce the amount of repulsion, these electron pairs prefer to maintain a $180°$ distance between one another. So, ${\mathrm{BeCl}}_2$ has a linear structure.

Therefore, ${\mathrm{BeCl}}_2$ has a linear structure.