Manufacturing and developing the delivery system of nuclear weapons is a costly affair. By manufacturing these weapons India will cripple her economy. For a developing country, such a setback will be disastrous.
Before the machine age, every article had to be made by hand. The craftsmen could make only one thing at a time. They could not make exactly similar articles. Moreover this took a long time. The total production was small.
Mass number of an element is denoted by A. The mass number of an element is equal to the sum of the number of protons (P) and number of neutrons (N).
According to the law of conservation of mass, during chemical reaction matter is neither created nor destroyed. Thus in a chemical reaction, total mass of the products is equal to the total mass of the reactants.
Atomic masses are very small. To express atomic masses a unit called atomic mass unit (amu; symbol, u) is commonly used. The atomic mass unit is defined as follows:
The relative atomic mass is denoted by Ar. The relative atomic mass is a pure number, and hence it has been no unit.
The average mass of an atom of an element is known as its atomic mass. Atomic mass of an element is designated as A. Since, atomic mass is actual mass, hence it has the unit of mass, viz, gram, kilogram, atomic mass unit, etc.
The average mass of a molecule of a substance is termed as its molecular mass (M). The molecular mass has the unit of mass, viz., gram, kilogram, atomic mass unit, etc.
Mass of one mole of any material is called its molar mass. The molar mass is measured in the units of gram per mole (g/mole), or kilogram per mole (kg/mol). One mole contains 6.023 × 1023 chemical units.