Final answer:
When magnesium reacts with chlorine, one ionic bond forms to create magnesium chloride (MgCl2). So the correct answer is Option A.
Step-by-step explanation:
The correct statement is A. One ionic bond forms.
When magnesium reacts with chlorine, it forms an ionic compound called magnesium chloride (MgCl2). Magnesium has two valence electrons and chlorine needs one electron to fill its outer electron shell. Magnesium donates two electrons to chlorine, forming a positively charged magnesium ion (Mg2+) and a negatively charged chloride ion (Cl-). These ions are held together by an ionic bond, which is the attraction between oppositely charged ions.