For Each of the Following Sentences, Fill in the Blanks

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once.
$\begin{array}{lll}\text { charge } & \text { length } & \text { polar } \\\text { covalent } & \text { molecule } & \text { salt } \\\text { double bond } & \text { noncovalent } & \text { single bond } \\\text { ionic } & \text { nonpolar } & \text { weight }\end{array}$

Whereas ionic bonds form a/an __________, covalent bonds between atoms form a/an __________.These covalent bonds have a characteristic bond __________ and become stronger and more rigid when two electrons are shared in a/an __________.Equal sharing of electrons yields a/an __________ covalent bond.If one atom participating in the bond has a stronger affinity for the electron, this produces a partial negative charge on one atom and a partial positive charge on the other.These __________ covalent bonds should not be confused with the weaker __________ bonds that are critical for the three-dimensional structure of biological molecules and for interactions between these molecules.