If the difference is not great, this forms a(n) bond.

Example: N2, and

Covalent

Explanation:

Using an electronegativity chart, such as the attached one, you see that Nitrogen (N) has an electronegativity value of 3.0.  Because both molecules are the same, 3.0-3.0=0.  Therefore, because the electronegativity value difference is 0, the bond must be covalent.

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.