arge atoms require low ionization energy while small atoms require high ionization energy. How?
I don't agree as it should be easier to remove electrons from greater radius shell of an atom.
I don't agree as it should be easier to remove electrons from greater radius shell of an atom.
-
I think you have answered your own question there?
Larger atoms have a greater ionic radius, hence, greater distance from the positively charged nucleus. Therefore, it requires less energy to overcome the electrostatic forces between the electron and the nucleus to release the electron. There is also the shielding effect from the inner electron shells.
Larger atoms have a greater ionic radius, hence, greater distance from the positively charged nucleus. Therefore, it requires less energy to overcome the electrostatic forces between the electron and the nucleus to release the electron. There is also the shielding effect from the inner electron shells.
-
Electrons in the valence shell are held by the nucleus. With increase in distance from the nucleus the force of attraction on to the valence electrons becomes weaker and electrons can be easily knocked off. Now, why does this happen Force between the electron and Nucleus is coulombic ie F is directly proportional to charge of the electron but F is inversely proportional to the SQUARE of radius. This means that an increase in radius will cause the force to reduce more. This is why we say that as the size of an atom increases force of the nucleus on to the valence electrons decreases and hence the ionization energy decreases.
-
An electron orbiting the nucleus suffers two type of forces (1) Centrifugal force which is inversely proportional to the square of radius of rotation. (2) The force of attraction to the nucleus.
An electron remains in orbit till these two forces are equal. For a heavy atom the number of protons is large, and so is the case for electrons. Now, the electrons are rotating in different orbits around nucleus. Each orbit can accommodate the maximum number of electrons as per the formula:
Maximum number of electrons an orbit can accommodate = 2 x n2. Where n is the rank of the orbit. Thus there will be a maximum of 2 electrons in first orbit, 8 electrons in second orbit, 18 electrons in third orbit, and so on. More the number of electrons more will be the orbits. This clearly shows that a heavy atom will have comparatively much larger distance between the nucleus and the valance electrons, resulting in to weaker bond with the nucleus. Naturally, it is easy to dislocge these electrons from their orbit. This is why it is the ionizing energy is lower for heavy atoms.
An electron remains in orbit till these two forces are equal. For a heavy atom the number of protons is large, and so is the case for electrons. Now, the electrons are rotating in different orbits around nucleus. Each orbit can accommodate the maximum number of electrons as per the formula:
Maximum number of electrons an orbit can accommodate = 2 x n2. Where n is the rank of the orbit. Thus there will be a maximum of 2 electrons in first orbit, 8 electrons in second orbit, 18 electrons in third orbit, and so on. More the number of electrons more will be the orbits. This clearly shows that a heavy atom will have comparatively much larger distance between the nucleus and the valance electrons, resulting in to weaker bond with the nucleus. Naturally, it is easy to dislocge these electrons from their orbit. This is why it is the ionizing energy is lower for heavy atoms.