3.01 × 1023 molecules H2O

0.5 mole

Explanation:

The question isn't even clear

But I'm guessing you want to ask the number of moles

n= Number of molecules/ Avogadros number

n= 1/2

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72