Draw the electron dot formula for selenium oxide; SeO2 and state the type of bonds in a selenium dioxide molecule. 1 double bond and 1 single bond
The Correct Answer and Explanation is:
Correct Answer:
✅ 2 double bonds
Explanation
Selenium dioxide, SeO₂, is a covalent compound consisting of one selenium (Se) atom and two oxygen (O) atoms. To understand the correct bonding and structure, we must consider the Lewis structure and formal charges.
Selenium (atomic number 34) is in group 16, like oxygen, and has 6 valence electrons. Oxygen also has 6 valence electrons. So the total number of valence electrons in SeO₂ is:
- 1 Se × 6 = 6
- 2 O × 6 = 12
- Total = 18 valence electrons
To draw the electron dot structure:
- Place selenium (Se) in the center because it is less electronegative than oxygen.
- Connect each oxygen atom to selenium with a single bond. That uses 4 electrons (2 per bond).
- We have 14 electrons remaining (18 – 4 = 14). Place 6 electrons (3 lone pairs) on each oxygen atom to fulfill their octets. That uses 12 more electrons.
- Now, 2 electrons remain, which go on selenium.
At this point, each oxygen has 8 electrons (including the bonding pair), but selenium has only 6 (2 from lone pair + 2 from each single bond). To complete selenium’s octet, we convert a lone pair from each oxygen into a double bond with selenium.
The final structure has two Se=O double bonds, and each atom satisfies the octet rule. This also ensures that the formal charges on all atoms are zero, which confirms the structure is stable and correct.
Triple bonds are unlikely with oxygen due to its inability to effectively form three bonds while maintaining a neutral formal charge. Hence, the correct bonding in SeO₂ involves two double bonds, not single/triple combinations.
Conclusion:
The selenium dioxide molecule has two double bonds, making the correct answer:
✅ 2 double bonds.
