It is the smallest particles of any substance that can be take part in a chemical reaction. it is very small in size. The size of atom represented by its radius size.
Symbols of elements, molecules and compound
For giving some small name to any compound, element or molecule scientists give symbol of them.
Some symbol of elements are derived from Latin words whereas other are from English words.
eg. Hydrogen - H, Helium - He, Sulphur - S, Argon - Ar, Silicon - Si, Sodium - Na, Gold - Au, Silver - Ag, Iron - Fe etc
Some symbol of molecules are Hydrogen - H2, Oxygen - O2 , Iodine - I2, Chlorine - Cl2 etc.
Some symbol of compound are Water H2O, carbon dioxide- CO2 , Methane CH4 etc.
It is equal to the sum of the atomic mass of the all the atoms present in the molecules of the substance, for eg:
- Hydrogen H2 - 1×2 = 2
- Nitrogen N2 - 14×2= 14
- Chlorine Cl2 - 35.5× 2= 71 etc.
It is a positively and negatively charged particles or part of the atom.
The ions which have positive charge are known as cations. They formed by loss of one or more electron by an atom. Eg. Na (-1 electron) → Na+
The ions which have negative charge are known as anion. They formed by gaining of electrons by an atom. Eg. Cl (+1 electron) → Cl-
Mass of one mole of substance is card molar mass of substance. Molar mass is equal to atomic mass. Eg. Molar mass of oxygen = 32
What is mole
Mole is a link between the mass of atoms and the number of atoms. A group of 6.022×1023particles of a substance is called mole of that substance. The number which represents the mole is known as Avogadro number (i.e. 6.02210 10)