7. Equal numbers of moles of CO2(g), N2(g), and NH3(g) are placed in a sealed vessel at room temperature. If the vessel has a pinhole-size leak, which of the following will be true after some of the gas mixture has effused? I. The mole fraction of CO2 in the sample will increase.
II. The N, will effuse the fastest since it is the lightest.
III. All gases will effuse at the same rate since the temperature is held constant.

I only
III only
I and II
II and III
I, II, and III​

hi

Explanation:

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons

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.

            and  

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.