As a solid element melts, the atoms become and they have attraction for one another. more separated, more more separated, less closer together, more closer together, less larger, greater

The complete statement is 

As a solid element melts, the atoms become more separated and they have less attraction for one another. 

Let me explain to you how this happens. In solid phase. Its molecules are arranged in a very compact manner that is why it takes a definite shape and volume. When it is heated, the kinetic energy of the molecules increases. This is characterized by more frequent collisions. The rise in temperature causes the molecules to move rapidly by vibrating. When it reaches an amount of energy that causes the solid to change phase, this is called the latent energy. The molecules break their form and move farther away from each other until it resembles that of a liquid melting. At this point, the molecules would have lesser attraction because of the distance between them.

The center is basically the heart of it