What are the main parts of an atom?

The main parts of an atom are the nucleus, which contains protons and neutrons, and the electron cloud surrounding the nucleus.

The nucleus is the central part of an atom. It is incredibly dense and contains two types of particles: protons and neutrons. Protons are positively charged particles, while neutrons carry no charge. The number of protons in an atom's nucleus determines the atomic number and identifies the element. For example, an atom with one proton is hydrogen, while an atom with two protons is helium. Neutrons contribute to the mass of the atom but do not affect the atomic number.

Surrounding the nucleus is the electron cloud, which is made up of negatively charged particles called electrons. These electrons move in orbits around the nucleus and are involved in chemical reactions. The number of electrons in a neutral atom is equal to the number of protons in the nucleus. This balance of positive and negative charges keeps the atom stable.

The arrangement of electrons in the electron cloud is also important. Electrons occupy energy levels, also known as shells. The first energy level can hold up to two electrons, the second can hold up to eight, and so on. The outermost energy level, or valence shell, determines how an atom interacts with other atoms and whether it will form bonds.

In summary, an atom is made up of a central nucleus containing protons and neutrons, surrounded by an electron cloud. The number and arrangement of these particles determine the properties of the atom and how it behaves in chemical reactions.