An ion which has more than one atom is know as polyatomic ion.

Polyatomic ion is a group of atoms which has positively or negatively charged.

Polyatomic ion is a molecular ion, which has two or more atoms covalently bonded.

Examples-

Sulphate ion ()

Ammonium ion ( )

The combinations of elements to form compounds follow some intresting laws, known as "Laws of chemical combinations".

They are

1) law of conservations of mass.

2) law of definate proportions

3)law of multiple proportions

4)gay-lussacs law of gaseous volumes

5)avagadro law.

1) Law of conservation of mass: It was prposed by Antonie Lavoiser. It's states that matter neither can be created nor can be destroyed.It means that The masses of the reactants and products in a chemical reaction will be same.

ex:-

In the above reaction 12g of carbon (C) is reactiong with 32g of oxygen (O) to form 44g of carbon dioxide () that means 12g+32g =44g.

reactant side mass is 12g+32g =44g & product side mass is 44g.

2) law of constant proportions: It is also know as law of definite proportions. It states that a given compound always have exactly the same proportion of elements by weight, irrespective of the source of the compound.

ex:-

The chemical formula of water is .

If you collect the water from tap (or) from sea (or) from rain (or) from a pond, the chemical formula of water remains same as .

Best Regarads From,

HARISH MALLELA,

TUTOR PARTNER CHEMISTRY,

URBANPRO.  

An ion is an electrically charged atom or molecule resulting from the loss or gain of one or more electrons. There are two main types of ions:

1. Cations: These are positively charged ions formed by the loss of one or more electrons from a neutral atom. For example, Na+ (sodium ion) is formed by the loss of one electron from a neutral sodium atom.

2. Anions: These are negatively charged ions formed by the gain of one or more electrons by a neutral atom. For example, Cl- (chloride ion) is formed by the gain of one electron by a neutral chlorine atom.

Valency is the combining capacity of an atom, determined by the number of electrons it can gain, lose, or share to achieve a stable electron configuration. The valency of magnesium is 2, as it loses two electrons to achieve a stable electron configuration, forming the Mg2+ ion. The valency of copper can vary depending on the compound it forms, but its common valencies are 1 and 2.