1.oxygen molecule is diatomic while while sulphhur is octatomic.why??

2.SF6 is known while SH6 is not known????

3.the ttendency to wxhibit -2 oxidation state diminishes down tthe group??

1. oxygen has small size and high electronegativity. so it can form p pi-p pi double bond and further the forces of interaction are van der waals,....so it exists as diatomic gas.

whereas sulphur doesnt form p pi- p pi bonds so it forms single bonds and exists as octaatomic.

 

2. since fluorine is the most electronegative element and  a strong oxidising agent, S shows maximum oxidation state with it ie +6 whereas, hydrogen is a weak oxidising agent, so it cannot oxidise S to +6 state.

 

3. tendency to exhibit -2 OS diminishes coz the electronegativity  decreases as we go down.