Ionization energy trend
Ionization energy trend
The energy required to remove an electron from the gaseous atom or an ion is called ionization energy trend. The initial or first ionization energy of an atom is the energy that is required to remove one mole of electrons forms at least one mole of isolated gaseous atoms or ions.
You also may think that ionization energy is a measure of the difficulty of removing electron by which an electron is bound. If the ionization energy is higher than it is more difficult to remove an electron. Hence, ionization energy acts as an indicator of reactivity. It can be used to help predict the strength of chemical bonds because ionization energy is important.
It was also is known as Ionization potential, IE, IP, or delta H degree.
Units of Ionization: Its unit is kilojoule per mole and also electron volts.
The trend of the periodic table in ionization energy
Ionization energy, together with the atomic and ionic radius, electron affinity, electronegativity, and the metallicity, is following the trend if the periodic table.
- Ionization energy decreases moving from top to bottom in the periodic table along the column. This is according to the quantum number of the outermost electron which increases moving down the group. Moving down a group there are more protons. This effect is on the pull in the electron shells and making them smaller and also screening outer electrons from the nucleus attractive force.
- Moving from left to right ionization energy generally increases across an element period. Also, there is a greater effective attraction between the positively charged nucleus and negatively charged electrons. For the alkali, metal ionization is at its minimum value on the left side of the periodic table. And also remains maximum on the far night side of a period for the noble gas. The noble gas contains a filled valence shell that’s why it resists electron removal.
Ionization Energy Trend of Exceptions
The first ionization energy of the boron is less than the beryllium and also the first ionization energy of oxygen is less than nitrogen.
Due to the electron configuration, the reason is for the discrepancy of these elements and also Hund’s Rule. From the 2s orbital the first ionization of beryllium contains first ionization potential electron. Whereas ionization of boron involves 2p electrons. The electron comes from the 2p orbital for both oxygen and nitrogen. For all 2p nitrogen electrons, the spin is the same. And It has a set paired of electrons in 1 of 2p oxygen orbitals.