Video Transcript
Which of the following is a pair of
elements that can form an ionic bond? (A) I and I, (B) Na and I, (C) Na
and Li, (D) N and I, or (E) H and I.
Ionic bonds are the strong
electrostatic interactions between positively charged ions, called cations, and
negatively charged ions, called anions, in an ionic lattice. In order for an ionic bond to form
between atoms of two elements, electrons are typically transferred from one atom to
another. Let’s consider an atom of sodium
and an atom of chlorine.
Sodium atoms have a single valence
electron. Chlorine atoms have seven valence
electrons in a valence shell that could hold eight. The valence electron of a sodium
atom can be transferred to a chlorine atom. Through this transfer of electrons,
a cation and an anion are produced that each have a full valence shell. These oppositely charged ions are
electrostatically attracted, and an ionic bond is formed between them. When atoms come together to form
ionic bonds, the atoms that typically lose electrons to form cations are metals,
while the atoms that typically gain electrons to form anions are nonmetals.
So to identify which pair of
elements can form an ionic bond, we need to determine which pair has both a metal
and a nonmetal. We can determine which elements are
metals and nonmetals by looking at the periodic table. The elements of the periodic table
are categorized as metals, nonmetals, or metalloids. If we identify the elements given
in the question on the periodic table, we can see that sodium and lithium are
metals, while hydrogen, nitrogen, and iodine are nonmetals.
So, the only pair of elements that
consists of a metal and a nonmetal is answer choice (B). Therefore, the pair of elements
that can form an ionic bond is Na and I, answer choice (B).
