The decreasing order of the first ionization energy of the following e...
Order of First Ionization Energy
The first ionization energy is defined as the amount of energy required to remove the outermost electron from an atom in the gaseous state. The order of first ionization energy of the given elements is:
a) He < h="" />< be="" />< />
b) Be < b="" />< h="" />< />
c) H < he="" />< be="" />< />
d) B < be="" />< he="" />< />
Explanation
The first ionization energy is affected by several factors such as the atomic size, nuclear charge, and electron shielding. The following factors contribute to the order of first ionization energy of the given elements:
Atomic Size
The first ionization energy decreases with an increase in atomic size. This is due to the fact that the outermost electron is farther away from the nucleus, making it easier to remove.
Nuclear Charge
The first ionization energy increases with an increase in nuclear charge. This is because the attraction between the nucleus and the outermost electron increases, making it harder to remove.
Electron Shielding
The first ionization energy decreases with an increase in electron shielding. This is because the inner electrons shield the outermost electron from the attraction of the nucleus, making it easier to remove.
Order of First Ionization Energy
a) He < h="" />< be="" />< />
He has the lowest first ionization energy as it has a small atomic size and the outermost electron is shielded by two inner electrons. H has a slightly higher first ionization energy as it has a smaller atomic size and the outermost electron is not shielded as effectively. Be has a higher first ionization energy as it has a larger atomic size and the outermost electron is closer to the nucleus. B has the highest first ionization energy as it has a smaller atomic size and the outermost electron is not shielded as effectively.
b) Be < b="" />< h="" />< />
The order is reversed because the factors that contribute to the first ionization energy are not in the same order as in option a.
c) H < he="" />< be="" />< />
This order is incorrect because it violates the trend of increasing first ionization energy from left to right across a period.
d) B < be="" />< he="" />< />
This order is incorrect because it violates the trend of increasing first ionization energy from left to right across a period.
The decreasing order of the first ionization energy of the following e...
Helium has small size than Hydrogen , assume Hydrogen Either you can take first group or 17th group then Left to right size decreases Hence He small size than H ,so I.E of He is greater than H. ,Berilium has 1s2, 2s2 (fulfilled) and Boron 1s2,2s2,2p1 (No half filled ,No fulfilled) so I.E of Be greater than B .