However, atoms are made up of three types of subatomic particles: the heavy protons and neutrons that make up the nucleus (the central part of the atom), and the much lighter electrons that circle the nucleus in orbital paths called shells.
Atom - Electrons, Nucleus, Bonds: Once the way atoms are put together is understood, the question of how they interact with each other can be addressed—in particular, how they form bonds to create molecules and macroscopic materials.
Atoms are made up of three basic types of particle: protons, neutrons, and electrons. These particles (as well as other particles smaller than atoms) are known as subatomic particles.
It attempts to describe and account for the properties of molecules and atoms and their constituents— electrons, protons, neutrons, and other more esoteric particles such as quarks and gluons.
The tiny particles called atoms are the basic building blocks of all matter. Atoms can be combined with other atoms to form molecules, but they cannot be divided into smaller parts by ordinary means.
Whereas classical atomism spoke mainly of material atoms (i.e., of particles of matter), the success of the atomic doctrine encouraged the extension of the general principles of atomism to other phenomena, more or less removed from the original field of application.
Dalton had begun his atomic studies by wondering why the different gases in the atmosphere do not separate, with the heaviest on the bottom and the lightest on the top. He decided that atoms are not infinite in variety as had been supposed and that they are limited to one of a kind for each element.
When atoms approach one another, their nuclei and electrons interact and tend to distribute themselves in space in such a way that the total energy is lower than it would be in any alternative arrangement.
Elements are characterized by the mass of their atoms. Dalton stated that all atoms of an element are identical in shape, size, and mass. When atoms are involved in chemical reactions, they combine in small whole-number ratios to form what are now called molecules.
Chemical bonding - Covalent, Molecules, Atoms: When none of the elements in a compound is a metal, no atoms in the compound have an ionization energy low enough for electron loss to be likely.
