To draw the Lewis structures for SiH4 (silane) and CO (carbon monoxide), we need to follow some systematic steps.
1. Lewis Structure for SiH4:
SiH4 is composed of one silicon (Si) atom and four hydrogen (H) atoms. Here’s how you can draw its Lewis structure:
- Count the total number of valence electrons: Silicon has 4 valence electrons, and each hydrogen has 1, for a total of 4 + (4 × 1) = 8 valence electrons.
- Place the silicon atom in the center with the four hydrogen atoms surrounding it.
- Connect each hydrogen atom to the silicon atom using single bonds. Each bond consists of 2 electrons.
- You end up using all 8 valence electrons: 4 from the Si-H bonds (2 electrons per bond).
- There are no lone pairs on silicon since all its electrons are involved in bonding.
The final structure is:
H | H - Si - H | H
2. Lewis Structure for CO:
Now, let’s draw the Lewis structure for carbon monoxide (CO), which consists of one carbon (C) atom and one oxygen (O) atom:
- Count the total number of valence electrons: Carbon has 4 valence electrons, and oxygen has 6, totaling 4 + 6 = 10 valence electrons.
- Place the carbon atom next to the oxygen atom, as they are both nonmetals.
- Start by forming a single bond between carbon and oxygen. This uses 2 of the 10 valence electrons, leaving us with 8 electrons.
- Next, to fulfill the octet rule, we need to form additional bonds. We can form a triple bond by adding two more pairs of electrons. Now, carbon will be surrounded by 8 electrons, and oxygen will also have a full octet.
The final structure is:
:O:::C:
Here, the colons represent the pairs of shared electrons, illustrating a triple bond between carbon and oxygen.
In summary, the Lewis structure for SiH4 shows central silicon with four hydrogens around it, while CO has a triple bond between carbon and oxygen, ensuring both atoms fulfill their octets.