Glossary of periodic Classification element

 5. Periodic Classification 

Anion  

The negatively charged ion formed when a neutral atom gains one, two or three electrons

Atomic Mass 

 The mass of an atom of an element. It is the sum of all protons and neutrons in the atom

Atomic Number 

 Total of number of protons in the nucleus of an atom

 Cation  

The positively charged ion formed when a neutral atom loses one, two or three electrons

 

Compound  

A molecule formed by atoms of two or more elements

Duplet  

The tendency of a hydrogen atom to gain an electron from another atom so that there are two electrons in its outermost shell

Electronic Configuration 

 The distribution of electrons in orbits around the nucleus of an atom

Element

  The pure form of a substance consisting of a single type of atom

Group 

 The vertical columns of the modern periodic table that includes elements which show similar chemical properties

Hydride  

Chemical compound whose molecule contains at least one hydrogen atom

Metalloid  

An element which shows the tendency of both metals and non-metals

Mixture 

 Substances made up of two or more components having variable composition from one sample to another

Molecule

The smallest physical unit of an element or compound, consisting of one or more like atoms in the case of an element and two or more different atoms in a compound

Noble Gas  

Elements which have 8 electrons (except Helium, which has 2) in their outermost shell, making them non-reactive to any other element. The six noble gases are Helium, Neon, Argon, Krypton, Xenon and Radon.

Octet  

The tendency of electrons of one or more kind of atoms to combine in such a way that there are eight electrons in the outermost shell

Orbit  

The fixed path which an electron takes during its revolution around the nucleus

Oxide  

A chemical compound whose molecule contains at least one oxygen atom

Period  

The horizontal rows in a modern periodic table

Periodic Table  

The table showing all the chemical elements in a manner grouping elements with similar atomic number and chemical properties together

Shell  

The fixed path or orbit in which electrons revolve around the nucleus of an atom

Valence Electrons  

The electrons present in the outermost shell of an atom

Valency

The number of electrons at atom loses or gains to form a molecule