ATOM, ION, AND MOLECULES

ATOM, ION, AND MOLECULES
 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.
ATOM 
According 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 numberThe mass number = number + the number of neutrons potonAtomic number = number of protons = number of electronsNumber of neutrons = mass number - atomic number

 
ISOTOP
Isotopes are atoms of the same element with different mass numbers. Isotopes can also be regarded as an atomic element having the same atomic number but have different mass numbers because each element has a different atomic number. Carbon is an example of the isotope.

Each carbon has the atomic number 6 but different mass numbers. From these examples it can be said that, although not necessarily the same element the same mass number.

ISOBAR AND ISOTON
Isobar are atoms of different elements but has the same mass number. While isoton adalaha tom of different elements but have the same number of neutrons.

ION 
An 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
Metals form positively charged ions (cations) and nonmetallic elements form the most negatively charged ions (anions).
The atoms in neutral containing positive and negative charges of the same amount. Ion charge can be estimated from the location of the elements in the periodic system. Ions of alkali metals (IA) always form ions are positively charged one, for example, lithium ion (Li +), sodium ions (Na +) and potassium ions ((K +). Ions of alkaline earth metals (IIA) has a positive two, ions such as calcium (Ca2 +), and magnesium (Mg 2 +).The ions of the halogen group elements (VIIa) is always negatively charged one, the fluoride ion (F-), chloride ions (Cl-), bromide ion (Br-), and iodide ions (I-). The ions of Group VIA forming two negatively charged ions, such as oxygen to form oxides (O2-) or sulfur to form sulfides (S2-). From the VA group, forming nitrogen nitride (N3-).Above ions derived from a single element (monatomic). Ion also there from the combination of two or more atoms of different elements (polyatomic). For example, the sulfate ion (SO42-), nitrate ion (NO3-), acetate ions (CH3COO-), ammonium ion (NH4 +) and hydroxyl ions (OH-).The amount of electric charge in a compound composed of positive and negative ions are neutral. For example NaCl.Charged ions have a strong force of electric attraction. The ions are positively charged (cationic) binds to the negatively charged ions (anions) via ionic bonds (chemical bonding that occurs because the force of electric attraction) and form ionic compounds (compounds formed due to ionic bonds).


MOLECULE 
Molecules 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:1. Hydrogen gas (H2)2. Gaseous oxygen (O2)3. Nitrogen gas (N2)4. Chlorine gas (Cl2)5. Iodine (I2)6. Phosphorus (P4)7. Sulfur (S8)Examples of molecular compounds:1. Sodium chloride (NaCl)2. Sodium hydroxide (NaOH)3. Sulfuric acid (H2SO4)4. Carbon dioxide (CO2)5. Ammonia (NH3)