What is the mass of one mole of hydrogen molecules?

2 grams

Explanation:

One MOLE of hydrogen atoms contains the same number of atoms as the number of hydrogen molecules in one MOLE of hydrogen molecules, i.e., Avagadros number. However, one mole of hydrogen atoms has a mass of 1 gram while one MOLE of hydrogen molecules has a mass of 2 grams.

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.