Answer:
The correct option is methane :
.
Explanation:
Average speed of the gas molecules id given by expression:

k = Boltzmann cosnatnt
T = Temperature of the gas molecules = 355 K
m = molecular mass of the molecule

Molar mass of methane = 18 g/mol
Molar mass of neon = 20.18 g/mol
Molar mass of ethene = 28 g/mol
Molar mass of chlorine gas = 70 g/mol
Lower the value of molar mass of gas molecule higher will be the average speed.So, from the given options methane gas greatest average seed because it has lowest molecular mass
Answer:
Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson's plum pudding model of the atom had negatively-charged electrons embedded within a positively-charged "soup.
Answer:
The answer is: D
Explanation:
A. They have the same number of electron energy shells. Is false, all the elements are in different periods so, they have different number of lectron energy shells.
B. They are all Halogens. No, is wrong, halogens are F, Cl ,Br
C. They have the same number of electrons. is wrong, if they had the same number of electrons they must be they same element and they aren't the same.
D. They are all Noble gases. Yes, it's true they are noble gases, they are the first group in the periodic table from the right.