How many lone pairs of electrons are on the entire structure in the correct Lewis structure for SiH4?
The Correct Answer and Explanation is :
The correct Lewis structure for SiH₄ (silane) shows that there are no lone pairs of electrons on any of the atoms. Here’s an explanation:
Lewis Structure of SiH₄:
- Silicon (Si) is the central atom, as it is less electronegative than hydrogen (H).
- Silicon is in Group 14 (4A) of the periodic table, which means it has 4 valence electrons.
- Hydrogen, being in Group 1 (1A), has 1 valence electron and needs only 1 more electron to complete its duet (2-electron shell).
To draw the Lewis structure:
- Place Si in the center, with four hydrogens (H) around it.
- Each hydrogen forms a single bond (a shared pair of electrons) with silicon. Since silicon has 4 valence electrons, it shares one electron with each hydrogen atom, forming four Si–H bonds.
Electron Distribution:
- Silicon shares its 4 valence electrons with the 4 hydrogens. This gives silicon a total of 8 electrons (satisfying the octet rule), with each hydrogen getting 2 electrons (completing their duet).
- There are no unshared electrons (lone pairs) on silicon since all of its valence electrons are involved in bonding.
- Similarly, hydrogen atoms don’t have any lone pairs either because they only need two electrons to be stable, which they achieve by sharing electrons with silicon.
Conclusion:
In the correct Lewis structure of SiH₄, all electrons are used in bonding. Silicon achieves an octet, and each hydrogen satisfies its duet. No lone pairs of electrons are present on either the silicon atom or the hydrogen atoms. Therefore, the number of lone pairs in the entire structure is zero.