The discovery of atoms can be traced back to ancient Greece. Philosophers believe that matter is composed of some elementary particles, but these theories are not widely accepted. With the development of science and technology, scientists have gradually discovered the existence of atoms.

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Atoms are the basic units of chemical substances, and they are particles composed of electrons inside and outside the nucleus. In science, the atom is regarded as the single and indivisible smallest unit of matter. Atoms are the most basic constituent units in nature and have their own unique attributes and properties.

First of all, the mass of atoms is very small, only about11836 of the mass of hydrogen atoms. This is because the number of protons and neutrons in the nucleus is very small, and the mass of electrons is even less.

Secondly, atoms have the property of positive and negative charges. Protons in the nucleus are positively charged while electrons are negatively charged. Because electrons revolve around the nucleus, there is electrostatic force between the negative charge of electrons and the positive charge of protons. This electrostatic force keeps electrons in their own orbits, thus forming a stable atomic structure.

In addition, atoms are highly symmetrical, and they rotate at the same speed. The outermost electron configuration law of atomic structure is closely related to atomic stability. By studying the electronic configuration of atomic structure, scientists can predict the chemical properties and reactivity of atoms.

In addition, the electronic structure of an atom also determines its chemical properties and reactivity. Different kinds of atoms have different electronic structures and chemical properties. For example, the electronic structure of hydrogen atom is the simplest, with only one proton and one electron. Its chemical properties are very active and it is easy to form compounds with other elements.

Some heavy elements, such as copper, silver and gold, have complex electronic structures and relatively stable chemical properties, and are not easy to react with other elements.

In addition, the nucleus consists of protons and neutrons. The number of protons is equal to the number of electrons outside the nucleus, which makes the atom remain electrically neutral. The number of neutrons determines the mass of the nucleus. Different types of atoms have different numbers of protons and neutrons, thus forming various elements.

Finally, atoms can combine with other atoms through chemical reactions, physical reactions and biological reactions to form more complex material structures such as molecules, solids or liquids. These material structures have unique properties and functions, for example, solids can conduct electricity, heat and support objects; Liquid has fluidity and surface tension; Gas has the characteristics of diffusion and dissolution.

In a word, atom is the basic unit of matter and has its own unique attributes and properties. By studying the structure and properties of atoms, we can better understand the nature and changing law of matter and provide basic support for scientific research and technological development.