A student finds two unlabeled bottles room temperature that are either CO2 or H2. Based on their appearance alone how can they determine which substance is which. Do not answer with an activity that is more than looking at the bottles. I'm confused because they are both gases and colorless

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

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since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.