atomic number and atomic mass

In 1913, Neils Bohr proposed a model of an atom based on the Planck's quantum theory of radiation. The basic postulates of Bohr's theory are: An atom consists of a small, heavily positively charged nucleus around which electrons revolve in definite circular paths called orbit..

Like halogens, hydrogen is diatomic (H 2 ) whereas metals are monoatomi..

The sum of the number of protons and neutrons in the nucleus of an atom is called the mass number. It is represented by the letter A. Mass number (A)= Number of protons (p) + number of neutrons (n) From the knowledge o..

It is the central core of the atom where the entire +ve charge and mass is concentrate..

Explosive fission reaction is the basic principle of an atom bomb. Two pieces of a fissionable material like U-235 (each with a sub critical mass) are brought together by means of a conventional explosion. The two masses together constitute super critical mass..

Structure of Atom..

Atoms and Molecules - The smallest particle of an element, which may or may not have independent existence is called an atom, while the smallest particle of a substance which is capable of independent existence is called a molecule. Molecules are classified as homoatomic and het..

Atom is the smallest particle of an element, which may or may not have independent existence. It is made up of subatomic particles like electrons, protons and neutrons. Atoms of one type of element differ from those of the other due to different number of subatom..

It is clear that usually the negative charge is transferred when two bodies are rubbed together. The electrons that are less tightly bound tend to move from its atom to the other. The number of electrons that are transferred will be insignificant compared to the total numb..

The bond length increases with increase in the size of the atom. From the above values it is clear that the bond lengths for a given family increase with increase in atomic number. For example, C-C < Si-Si < Ge-Ge This is because with the increase in size of the..