The scientist who suggested that the symbols of elements be made from one or two letters to form the name of the element.

The most remarkable concept that Dalton's atomic theory proposed was that of the

The charged species are known as 

Sulphur is 

In ammonia, the ratio of the mass of nitrogen to the mass of hydrogen is always be

Atoms of same element or of different elements can join together to form 

The amount of substance that contains the same number of particles as there are atoms in exactly 12g of carbon-12   atom is 

In water, the ratio of mass of hydrogen to the mass of oxygen is always