Answer to Question #53525 in General Chemistry for manisha
How can reactivity of the elements in a group be determined as we said in group 16 reactivity order is :
O > S > Se > Te > Po
How do we know that oxygen is more reactive then all other?
Reactivity for non-metal elements decreases as you go down the group. There is one main reason which determines this tendency: an increase in atomic radii. The elements of 16th group tend to complete their outermost shell by taking two electrons from other atoms. Since those of them with larger radii attract these shared electrons weaker, the stabilization energy of such electronic configuration decreases. This leads to the lower reactivity for the elements being in the bottom of the group. From another hand, the electronegativity of element in the group diminishes in order of increasing atomic number (atomic radius) which results in the lower difference of electronegativities for E-H bond, where E – the element from 16th group. The low polarity of the E-X bond indicates the low stability of this bond which is associated with a low reactivity of the E with Hydrogen. Thus, the most reactive is Oxygen being in the top of the group.