Answer:
<h2>Oxygen has six valence electrons, two in the 2s subshell and four in the 2p subshell.</h2>
<h3>Valence electrons are the electrons in the outermost shell, or energy level, of an atom. </h3>
<h3>Configuration of oxygen's valence electrons as 2s²2p⁴.</h3>
Explanation:
#Let's Study
#I Hope It's Help
#Keep On Learning
#Carry On Learning

Answer:
I think it the carbon 14 which is a half life of 5730 because in 4.5billion years ago I don't think any human being existed on earth I'm not sure I hope that I helped you and good luck .
Should be :
Lead Sulfate Tetrahydrate
Yesn’t. they are either wrong or links