The definition of Atom, Elements, Ions, Compounds, Molecules, Chemical

Atom is a collection of matter consisting of positively charged nuclei, which usually contains protons and neutrons, and some of the electrons in the balance the positive charge surrounding the nucleus. Atom is also the smallest unit that can be described from an element and still retain their nature, are formed from the dense core and surrounded by a positively charged electron system.

The element is a group of atoms that have the same number of protons in the nucleus. This amount is called the atomic number elements. For example, all atoms have six protons in its core is a carbon atom of the chemical elements, and all atoms have 92 protons in its core is the element uranium atoms.

Display elements are the most fit in the periodic table, which classifies the elements according to similar chemical properties. List of elements by name, symbol, and atomic number is also available.

Ions or charged species, or an atom or molecule losing or gaining one or more electrons. Positively charged cations (eg sodium cation Na +) and negatively charged anions (eg chloride Cl-) can form a neutral salt (eg sodium chloride, NaCl). Examples of polyatomic ions that do not split during acid-base reactions are hydroxide (OH-) and phosphate (PO43-).

The compound is a substance formed by two or more elements with a fixed ratio determining the arrangement. for example, water is a compound containing hydrogen and oxygen with a ratio of two to one. Compounds are formed and broken down by chemical reactions.

Molecule is the smallest part of a split and not pure chemical compounds which still maintain the chemical and physical properties are unique. A molecule consisting of two or more atoms bound to one another.

A 'chemical' may be an element, compound, or mixture of compounds, elements, or compounds and elements. Most of the material we encounter in everyday life is a kind of mixture, eg water, alloy, biomass, etc..