Presure is merely force over a defined area.  Gas pressure is just the collective force of gas molecules running into a container wall.  Since gas molecules have such small masses, these gas molecules are moving at very fast speeds.

The reason why these things do bounce off the walls and one another is because molecules and atoms have clouds of electrons around them that repel each other, positive repels positive and negative repels negative.  So these things didn't have these repulsive electrostatic forces, they'd just run right through each other.  So you're right.

As temperature increase, the motion of the atoms increases as well.  (Hence when you are boiling water, the heat causes the water molecules to move around faster and faster until they have so much energy from the heat that they become a gas).  The higher energy/movement of the molecules is also what causes density to decrease as temperature increases.  In the case of the gas, the gas molecules are moving around at a faster rate and with more energy, so the force they exert on each other and the walls of the container increases as well.  

The point is that the change in temperature increases the kinetic energy of the gas, making them faster and run into the walls of the container more often giving the impression of even pressure.

The whole point of talking about electron clouds is to be able to treat gases as hard objects, things that bounce off each other for the most part.  However, in terms of gas pressure, as temp goes up, gases move faster and *Ignore me, I am impatient* into walls more often creating pressure.

What i know is that by increasing temperature the energy of gas paricles increases.

E=3/2RT [For monoatomic gases]
and this results in overall increase in energy by which transational energy increases so motion of gas particles increases.

I wonder how change in temp. will affect the electron clouds,perhaps due to increase in random motion of the gas molecules there will be more repulsion between the electron clouds.

If you get such a thing as wind, or a pressure gradient, PV=nRT no longer works.  We're assuming the gas is in a static condition.  Also, yes pressure is related to temperature but not exclusively so.

Gas molecules/atoms in "normal" conditions neutral with the electrons canceling out the charge of the nucleus.  If they were charged, gosh... I can't imagine, gases would fly off into space or something and a little wind could cause all electric circuits to blow.

Temperature is merely a macroscopic property that manifests as a result of collective microscopic events.  By the kinetic gas theory we can say that the temperature is the average kinetic energy of the gas.  Energy can be in the form of electrical, kinetic, or due to the prescence of other fields, ie gravity.  However, gases in average non-ultra high temperatures are always in the ground state electrically.  The only energy that ever changes is its mechanical energy which is in the form of translational and vibrational energy.  If there is just one atom comprising of the gas molecule, then there is no possible vibration mode, so there's only translational energy, therefore it would be safe to say that we can relate the gas's average speed to its energy.

I think temperature does not effect the atomic radii.It does increase its kinetic energy.

I think temperature does not effect the atomic radii.It does increase its kinetic energy.

Actually, I think it does.  When you are increasing temperature you are adding energy to the atom/molecule.  As the energy is absorbed, the electrons wind up having higher energy as well, so they will move up to a higher energy level.  Since those higher energy levels are further away from the nucleus, the atomic radius of those atoms will increase.  If you apply enough energy, the electrons will have so much energy that they will leave the atoms altogether.  This is how a plasma is formed.  (All the atoms in the middle of the sun have no electrons.  It's simply a very high temperature plasma).