The isotopes of a particular elements means that every element has there own isotopes like H has three isotopes protium, dutrium,tritium. like that cl has also thier own isotopes.
Answer: definite proportions.
Explanation:
1) The definite proportions law states that compounds will always have the same kind of atoms (elements) in the same mass proportion (ratios).
2) For example, a molecule of water will alwys have the same mass ratio of hydrogen atoms to oxygen atoms. That is what permits to obtain the chemical formula of the water molecule as H₂O.
The mass of the two hydrogen atoms will be in a fixed ratio respect to the mass of the oxygen atoms.
Then, if you have one reactant in less proportion than the other, respect to the ratio stated by the chemical formula of water, the former will react completely (it is the limiting reactant) with the corresponding (proportional) mass of the later. Then there will be an excess of the later reactant which will not react (will remain unchanged).
The reactants can only react in the proportion defined by the chemical formulas of the final products.
Answer: Photoelectric is characterized by or involving the emission of electrons from a surface by the action of light.
Photoelectric effect is the emission of electrons when a radiation of frequency higher than the threshold frequency falls on the surface of an element. The substance which undergoes photoelectric effect is called as photoelectric.
Ground state is the state representing the lowest energy state.
Excited state is the state which represents a high energy state.
An electron in ground state absorbs energy to move to the excited state.