Sodium is in group 1 of the periodic table. a sodium ion (na+) has a charge of +1. which of the following would be most likely to combine with an sodium ion to form a new compound?
a. a helium atom that has no charge
b. a calcium ion with a charge of +2
c. a fluoride ion with a charge of -1
d. a lithium ion with a charge of +1

C.

A helium atom will not bond with the sodium atom because, in order to form a good ionic bond, the charges of the atoms in the molecule must cancel out. Because helium's charge is zero, it does not need to bond with anything. Helium also has a complete octet of electrons, which makes bonding impossible in the first place.

The calcium and lithium ions will not form a bond with the sodium because their charges wont cancel out the  sodium's plus one charge.

The fluoride ion, however, will cancel out sodium's charge. Their charges sum up to equal zero. Fluoride will form an ionic bond with the sodium, which forms a NaF molecule.