values of energy gaps

Valence band and the conduction band lies in the energy gap. According to the Bohr's theory, free electrons in an isolated atom have certain definite discrete amount of energy. If large number of atoms are brought close to one another to form a crystal, they begin to ..

>Complete the following fission reaction: What should be the value of x? Is the mass conserved? Explain. Suggested Answer:- x = 3 Mass is not conserved. The difference in mass is converted to energy as the binding energy of the nuclides changes. Example 9:- What is the..

Due to a fairly large size of the atoms, alkaline Earth metals have low ionization energies when compared to 'p' block elements. Down the group the ionization energy decreases as atomic size increases. This is due to new shells being added and increase in the magnitude of the s..

. We use the symbol 'U' for internal energy. During a change of state of the system, the internal energy may change from an initial value U 1 to a final value U 2 . We denote the change in internal energy as..

The amount of energy required to remove the most loosely bound electron from an isolated gaseous atom is called ionization energy (IE..

Therefore, for a given molecular diameter, the collision frequency will also have a square-root dependency on temperature. The ratio of Z values at two temperature values, for e.g., at 298 K and 308 K will be A ten-degree rise in temperature near the room temperature usually dou..

Alkali metals have the lowest ionization energy in each period. Within the group, as we go down, the ionization energies of alkali metals decrease due to their atomic size being the largest in their respective periods. In large atoms the valence electrons are loosely held by t..

. Each of them is a parabola. The sum of the potential energy and the kinetic energy values remains constant as represented by the horizontal line. At the points where the two curves cross, we can write Equation (2.53) can also be written ..

Since chemical changes are always accompanied by energy changes, it indicates that reactants and products must be having certain amounts of energy. A fixed quantity of any substance is associated with a definite amount of energy, which depends upon chemical natur..

It should do a large amount of work per unit mass or volume - it means that the output energy must be more than the input energy. It should have high calorific value..