ATOM, ION, AND MOLECULES08:38 In ancient times, many scientists are confused with particulate matter. What is the smallest part of the matter? That's the question at the time was a mystery to scientists. Finally, thanks to the intelligence and curiosity of the scientist, the mystery that was slowly answered. The material turned out to contain small particles, the constituent can be atoms, ions, and molecules. Come, learn more in this chapter.

AtomAccording to Dalton's atomic theory, atoms are the smallest part of an element that has not be subdivided by ordinary chemical reactions. Ahead of the 19th century, it is known that the atom is not a particle that can not be divided again as it contains a number of sub-atomic particles are electrons, protons, and neutrons.

 Atoms consist of a nucleus surrounded by electrons moving in a particular orbit. Almost all of the mass of the atom is concentrated in the nucleus in the form of protons and neutrons.

 Coat an atom is written as follows:

 Description:A: mass numberZ: atomic number
The mass number = number + the number of neutrons poton
Atomic number = number of protons = number of electrons
Number of neutrons = mass number - atomic number
IonAn atom is said to be neutral if the number of protons equals the number of electrons.If a neutral atom captures an electron, the number of electrons will be more than the number of protons. The atom is said to capture electrons are negatively charged atoms.If a neutral atom loses electrons, then the number of protons will be more than the number of electrons. The atom loses electrons is said to be positively charged.Electrically charged atoms called ions. Positive ions are called cations and negative ions are called anions.Ions are atoms or groups of atoms that accept or release electrons.Salt (NaCl) is an example of merging with the Na + cation-anion Cl
MoleculeMolecules are particles consisting of two or more atoms, either atoms or atoms of different kind.Molecules are composed of atoms called molecules similar elements, whereas a molecule composed of different atoms are called molecular compounds.Examples of molecular elements:

    Hydrogen gas (H2)
    Gaseous oxygen (O2)
    Nitrogen gas (N2)
    Chlorine gas (Cl2)
    Iodine (I2)
    Phosphorus (P4)
    Sulfur (S8)
Examples of molecular compounds:

    Sodium chloride (NaCl)
    Sodium hydroxide (NaOH)
    Sulfuric acid (H2SO4)
    Carbon dioxide (CO2)
    Ammonia (NH3)