According to the octet rule, this element would be expected to form a(n) _______ with a charge of fill in the blank 3 .

This question is incomplete, however the answer to fill the blanks can still be determined if the following steps are followed. Firstly, the octet rule is a rule that proposes that all elements (with the exception of group zero elements) in the periodic table strive to achieve eight electrons in there outermost shell. The reason group zero elements are not actually affected by this "strive" is because they already have a completely filled/have eight (8) electrons in there outermost shell.

Thus, elements that do not have 8 electrons in there outermost shell would be expected to form an ion with a charge of either positive or negative depending on whether the element will lose or accept electrons to achieve this feat.

Elements that have less than five electrons (called valence electrons) on there outermost shell will lose the valence electron(s) and become positively charged with a charge equivalent to the number of electron(s) lost. For example, Aluminium (Al) has three electrons in it's outermost shell, in order to obey the octet rule, aluminium atom will lose it's three valence electrons and become positively charged with a number equivalent to the lost electrons which is three (Al³⁺). Metallic elements are usually the those that have the tendency to become positively charged.

Elements that have more than five valence electrons in there outermost shell will gain more electron(s) to achieve the octet rule (that is become eight) and become negatively charged in the process with a charge equivalent to the number of electrons gained. For example, Chlorine (Cl) has seven electrons in it's outermost shell and needs just one more electron to achieve the octet rule, if chlorine gains this one electron, it becomes Cl⁻. Nonmetallic elements are usually the those that have the tendency to become negatively charged.

From the last two paragraphs, one can determine the exact charge of the element described in the question by determining the number of electron(s) found on it's outermost shell.