Which of the following is not a postulate of the kinetic molecular theory? select one: a. gas particles have most of their mass concentrated in the nucleus of the atom. b. the moving particles undergo perfectly elastic collisions with the walls of the container. c. the forces of attraction and repulsion between the particles are insignificant. d. the average kinetic energy of the particles is directly proportional to the absolute temperature. e. all of the above are postulates of the kinetic molecular theory.

a. Gas particles have most of their mass concentrated in the nucleus of the atom

Explanation:

The main postulates of the molecular kinetic theory are:

A gas consists of a set of small particles that move with rectilinear motion and obey Newton's laws (this means that this theory doesn't divide the atom in a nucleus and electrons, this is why a. is not correct)

The molecules of a gas do not occupy volume (this is assumed because between the molecules of a gas is a lot of space).

Collisions between the molecules are perfectly elastic (this means that energy is not gained or lost during the crash).

There're no forces of attraction or repulsion between the molecules (because each molecule is "far" of the others).

The average kinetic energy of a molecule is (where T is the absolute temperature and k the Boltzmann constant. This means that kinetic energy is directly proportional to temperature).

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)