Which of the following gases contains the highest number of atoms at s.t.p?

At standard temperature and pressure (STP), which is defined as a temperature of 273 K (0°C) and a pressure of 1 atm (101.3 kPa), all gases occupy the same volume of 22.4 L per mole. Therefore, the number of atoms present in a gas is directly proportional to the number of moles of that gas. Thus, the gas with the highest number of atoms at STP would be the one with the highest number of moles. Using Avogadro's law, 1 mole of any gas at STP contains approximately 6.02 x 10^23 atoms or molecules. - 6 moles of neon would contain 6 x (6.02 x 10^23) atoms = 3.61 x 10^24 atoms - 3 moles of oxygen would contain 3 x (6.02 x 10^23) atoms = 1.81 x 10^24 atoms - 2 moles of chlorine would contain 2 x (6.02 x 10^23) atoms = 1.20 x 10^24 atoms - 1 mole of ethane (C2H6) would contain 1 x (2 x 6.02 x 10^23) atoms = 1.20 x 10^24 atoms Therefore, the gas with the highest number of atoms at STP is neon with 6 moles, which contains 3.61 x 10^24 atoms.