Electronegativity - capacity to loss electrons - is representative for the reactivity of chemical elements; for metals low electronegativity is a high reactivity.
Assuming you mean electronegativity, it is 2.2 on the Pauling scale.
You never said which group.
Electronegativity
The hydrogen atoms have the much lesser electronegativity in water. That pole is slightly positive because of oxygen being so much more electronegative and having the electrons in the covalent bonds spend more time in it's orbital.
The electronegravity decreases as you go down the periodic table. As you go down the columns in the periodic table the atoms get bigger because there are more full shells of electrons (although the number electrons in the OUTER shell always stays the same for each element in the group). so because there are more shells the outer shell of electrons becomes increasingly further away from the nucleus this means they are shielded from the attractions of the positive nucleus' pull by the increasing number of inner shells. hope this was the answer you were looking for and that it made sense.