Question

iodine and potassium form an ionic bond. iodine has seven electrons in its outer shell, and potassium has one electron in its outer shell. which conclusion is best supported by this information?
iodine is a noble gas.
potassium is a nonmetal.
iodine becomes an ion with a negative 1 charge.
potassium becomes an ion with a positive 7 charge.

Explanation:

• Noble gases have full outer electron shells (8 electrons for most). Iodine has 7 outer - shell electrons, so it is not a noble gas.
• Potassium is an alkali metal, not a non - metal.
• Iodine has 7 electrons in its outer shell. To achieve a stable electron configuration (8 electrons in the outer shell), it will gain 1 electron. When an atom gains an electron, it becomes a negatively - charged ion. So, iodine will become an ion with a charge of - 1.
• Potassium has 1 electron in its outer shell. To achieve a stable electron configuration (8 electrons in the outer shell), it will lose 1 electron. When an atom loses an electron, it becomes a positively - charged ion. So, potassium will become an ion with a charge of + 1, not + 7.

Answer:

Iodine becomes an ion with a negative 1 charge.