For which of these elements would the first ionization energy of the atom be higher than that of the diatomic molecule? helium oxygen carbon lithium explain why and

The first ionization energy of the element will be highest for atom than it’s diatomic.

Further explanation:

Ionization energy:

Ionization energy is defined as the amount of energy that is required to remove the most loosely bound valence electrons from the isolated neutral gaseous atom. It is denoted by IE. The value of IE is related to the ease of removing the outermost valence electrons.

The elements whose electronic configuration contains one or more electrons more than the valence shell of a noble gas can easily remove their valence electrons by even a small amount of energy. Hence the ionization energy associated with such element is least.  

The numbers of electrons present in the valence shell determine whether the ionization energy will be low or high. The electronic configuration of helium is  .it has already fully filled electronic configuration. All the electrons are paired. So it cannot remove any electron howsoever high energy is provided.

The electronic configuration of lithium is. It has one additional electron that can be removed so its first ionization energy is low. The lithium-ion thus formed can readily combine with lithium cation and form dilithium.

The electronic configuration of carbon is .It can also lose electron as the electrons present in 2s are relatively loosely held compared to the electrons in 2s subshell. It has been found that energy of nearly is required to ionize the first electron out of carbon.

The electronic configuration of oxygen is .It can also lose electron as the electrons present in 2s are relatively loosely held compared to the electrons in 2s subshell. It has been found that energy of nearly is required to ionize the first electron out of carbon.

Therefore the electron that is removed with most difficulty is helium.

Learn more:

1. The subatomic particle with the least mass:

2. Oxidation and reduction reaction:

Answer details:

Grade: High School

Subject: Chemistry

Chapter: Periodic classification of elements

Keywords: Periodic properties atomic structure groups, periods, periodic law chemical properties ionization enthalpy, electronegativity,atomic radii, effective nuclear charge, valence shell, electronic configuration.