Answer:
C. one Na atom and one iodine atom
Step-by-step explanation:
You want to know which of the pairings of one atom each would create an octet for each atom.
- K and O
- Al and Cl
- Na and I
- Li and C
Octet
An octet is formed when there are 8 electrons in the outer energy level of an atom. In general, elements on the left side of the periodic table (Li, Na, K) have one electron in their outer energy level, so are able to donate an electron. Elements on the right side of the periodic table (Cl, I) are missing one electron in their outer energy level, so an octet will be created if an electron is donated to them.
Elements in the middle of the periodic table have more electrons to give and receive. Carbon has 4 empty outer level positions, and Oxygen has 2.
So, the pairing that would create an octet for each atom would be one of Li, Na, or K and one of Cl or I. Only one such pairing is offered as an answer choice:
(c) Na and I . . . . sodium and iodine
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Additional comment
Octets of other pairings can be formed, but more than one atom must be used. For example, K₂O, AlCl₃, Li₄C.