Which element would have a full outer shell of electrons if it gained three electrons? (1 point)
* nitrogen
• argon
* boron
• lithium
argon
Argon.
To determine which element would have a full outer shell of electrons if it gained three electrons, we need to consider the electron configuration of each element.
Nitrogen has an atomic number of 7, which means it has 7 electrons. Its electron configuration is 1s^2 2s^2 2p^3. Nitrogen's outer shell contains 5 electrons, and it needs 3 additional electrons to complete its outer shell.
Argon has an atomic number of 18, which means it has 18 electrons. Its electron configuration is 1s^2 2s^2 2p^6 3s^2 3p^6. Argon already has a full outer shell with 8 electrons in its 3s and 3p orbitals. Therefore, adding 3 electrons to argon would not result in a full outer shell.
Boron has an atomic number of 5, which means it has 5 electrons. Its electron configuration is 1s^2 2s^2 2p^1. Boron's outer shell contains only 3 electrons, and adding 3 electrons would complete the outer shell, resulting in a full outer shell.
Lithium has an atomic number of 3, which means it has 3 electrons. Its electron configuration is 1s^2 2s^1. Lithium's outer shell contains only 1 electron, and adding 3 electrons would not result in a full outer shell.
Therefore, the correct choice is boron.