In all the fields of science (and also in economy, politics, moral, medicine, etc.) the ideal state is only a word. The ideal doesn't exist but it is very necessary to elaborate valid theories. In conclusion one can say that xenon is still a (quasi)ideal gas.
helium
Xenon is an inert gas. Like all the inert gases, it is a gas at room temperature.
Gases show least ideal behaviour at 1- high pressure and 2- low temperature.
Xenon, a gas at room temperature, does not have a texture. It feels like air.
Water does not behave exactly like an ideal gas because water is a polar molecule. And, the polar molecules of water, if properly oriented in space, have strong attraction to one another, and may form a hydrogen bond and condense back into liquid form. Also, when a gaseous water molecule has a collision with liquid water, if it is oriented in the right way (i.e. an oxygen atom comes into contact with a hydrogen atom), it will move back into the liquid phase. So, because water molecules move back into the liquid phase much more easily than ideal gas molecules, water vapor does not behave exactly as an ideal gas would.
CO2 can behave like an ideal gas, but is not an ideal gas. Depending on the temperature and amount of pressure applied, virtually all gasses can behave as ideal gasses. The ideal gas equation can be used on CO2 as a good approximation. (P = nRT/(V-nb) - an^2/V^2)
helium
Helium
An ideal gas is a theoretical gas composed of a set of randomly-moving, non-interacting point particles. The ideal gas concept is useful because it obeys the ideal gas law. At normal conditions such as standard temperature and pressure, most real gases behave qualitatively like an ideal gas. Many gases such as air, nitrogen, oxygen, hydrogen, noble gases, and some heavier gases like carbon dioxide can be treated like ideal gases within reasonable tolerances.
Xenon is an inert gas. Like all the inert gases, it is a gas at room temperature.
Gases show least ideal behaviour at 1- high pressure and 2- low temperature.
Xenon, a gas at room temperature, does not have a texture. It feels like air.
low pressure and high temperature
Not true. It applies to real gases that are exhibiting ideal behavior. Any gas that is not 'close' to its boiling and is at a 'low' pressure will behave like an ideal gas and Boyle's Law can be applied. Remember there is no such thing as an ideal gas, so when Boyle did his experiments and came up with his law he was using a real gas, probably just air.
Water does not behave exactly like an ideal gas because water is a polar molecule. And, the polar molecules of water, if properly oriented in space, have strong attraction to one another, and may form a hydrogen bond and condense back into liquid form. Also, when a gaseous water molecule has a collision with liquid water, if it is oriented in the right way (i.e. an oxygen atom comes into contact with a hydrogen atom), it will move back into the liquid phase. So, because water molecules move back into the liquid phase much more easily than ideal gas molecules, water vapor does not behave exactly as an ideal gas would.
Normally a gas.
NH3, as in Ammonia, like all real gases, are not ideal. Ideal gases follow the ideal gas laws, but ammonia does not adhere to a few of them. First of all, the volume of its molecules in a container is not negliggible. Next, NH3 molecules have intermolecular hydrogen bonding, which is a strong intermolecular bond. Thus, the forces of attaction between molecules is not neglible. All real gases have a certain degree of an ideal gas, but no real gas is actually ideal, with H2 being the closest to ideal.