in chlorine gas, two chlorine atoms join to form a Cl2 (chlorine 2) molecule. How many pairs of valence electrons do the atoms share? What type of covalent bond is formed?

Since each Chlorine molecule is - 1 and wants to gain an electron, 2 Chlorine atoms like to come together to form Cl2 by sharing 2 electrons each to form a single bond between the 2 atoms. Since both Chlornine has the same electronegativity, the bond is non-polar covalent since there electrons are evenly shared.