Answer:
A. one potassium and one iodine
Explanation:
K is a metal and I is a nonmetal, so K will lose electrons to form a cation and I will gain electrons to form an anion. Together, they will be bonded through an ionic bond. To determine how many electrons they gain or lose and how many atoms are in the chemical formula, we need to consider the octet's rule: an atom will gain, lose, or share electrons until it has 8 electrons in its valence shell.
- K belongs to Group 1 in the periodic table and it has 1 valence electron. So, it will lose 1 electron to complete the octet. The resulting cation is K⁺.
- I belongs to Group 17 in the periodic table and it has 7 valence electrons. So, it will gain 1 electron to complete the octet. The resulting anion is I⁻.
We need 1 K⁺ and 1 I⁻ to form the neutral salt KI.
