Write the structural formula of H2O and find their valence?

What is a possible quantum number set for an electron in the 3s orbital of a magnesium atom

How much would the freezing point of water decrease if 4 mol of nacl were added to 1 kg of water (kf=1.86 degrees c/(mol/kg) for water and i=2 for nacl a- 7.44 degrees c b- 14.88 c 3.72 d 1.86

Which element has the largest atomic radius? a. asb. nc. pd. sb