Understanding Ionic Compounds
Ionic compounds form when a metal (like sodium) transfers electrons to a nonmetal, creating positively charged ions (cations) and negatively charged ions (anions). These opposite charges attract, forming a strong electrostatic bond.
Sodium (Na)
* Sodium is in Group 1 of the periodic table, meaning it has one valence electron it readily loses to achieve a stable octet. This forms a +1 cation (Na+).
Calcium (Ca)
* Calcium is in Group 2, meaning it has two valence electrons it can lose, forming a +2 cation (Ca2+).
Oxygen (O)
* Oxygen is in Group 16, meaning it needs two more electrons to achieve a stable octet. It forms a -2 anion (O2-).
Nitrogen (N)
* Nitrogen is in Group 15, meaning it needs three more electrons to achieve a stable octet. It forms a -3 anion (N3-).
Determining the Reactions
To form an ionic compound with two sodium atoms (2Na+), we need a nonmetal that can accept two electrons.
* Calcium (Ca) is not a suitable choice. Calcium is a metal and will form its own ionic compounds.
* Nitrogen (N) is not a suitable choice. Nitrogen requires three electrons, so two sodium atoms wouldn't be enough to form a neutral compound.
* Oxygen (O) is the suitable choice. Two sodium atoms (2Na+) can transfer their electrons to one oxygen atom (O2-) to form a neutral compound:
2Na + O → Na2O (Sodium Oxide)
In summary: Oxygen is the only element from your list that can react with two sodium atoms to form an ionic compound, sodium oxide (Na2O).
