Final answer:
Carbon monoxide (CO) needs 10 valence electrons in total, with 4 from carbon and 6 from oxygen. A triple bond between carbon and oxygen accounts for 6 of these electrons, and the two lone pairs on oxygen account for the other 4, leading to a total of 10 needed electrons.
Step-by-step explanation:
To determine the number of electrons "needed" for the compound carbon monoxide, CO, we consider the valence electrons of carbon (C) and oxygen (O). A carbon atom (from group 14) has 4 valence electrons and an oxygen atom (from group 16) has 6 valence electrons. The molecule of CO needs to reach an octet for both carbon and oxygen to be stable. So, we have:
- 1 C atom = 4 valence electrons
- 1 O atom = 6 valence electrons
- Total valence electrons needed = 4 (from C) + 6 (from O) = 10 valence electrons to reach the initial octet state.
However, the carbon and oxygen in CO share a triple bond, and there are two lone pairs of electrons on the oxygen. This means we have a total of:
- 3 shared pairs (triple bond) x 2 = 6 electrons for bonding
- 2 lone pairs on oxygen x 2 = 4 non-bonding electrons
- Total electrons shared or non-bonded in CO = 6 + 4 = 10 electrons
Therefore, the correct answer is A. 10 electrons.