How can we tell the difference between gases like hydrogen, oxygen, and carbon dioxide cause they all look to same?

The table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

Avariable that is not being directly tested during an experiment should be

Which of the following is most likely true about water in chemical solutions?