Question

Which of the following atoms has the highest first ionization energy?
A.Sc
B.K

Answer 1

In basic words, ionisation energy is a measure of how difficult it is to remove an electron from an atom or ion, or how likely an atom or ion is to yield an electron. The loss of one electron generally occurs in the chemical species' ground state. We may also say that ionisation, or ionisation energy, is a measure of the strength (attractive forces) with which an electron is held in place.

Complete answer:
The ionisation energy of electrons in various atomic or molecular orbitals is variable. The nth ionisation energy, in general, is the amount of energy necessary to remove the nth electron after the first n-1 electrons have been removed. It is a measure of an atom's or ion's inclination to yield an electron, or the strength of the electron binding. The more ionisation energy there is, the harder it is to remove one electron. The ionisation energy of an element can be used to determine its reactivity. Low-ionization-energy elements tend to be reducing agents, forming cations, which interact with anions to create salts.
The energy required to remove one electron from an atom is referred to as the initial ionisation energy. The electrical attraction between positive protons in the nucleus and negative electrons determines the first ionisation energy; if protons and electrons are more attracted to each other, the first ionisation energy will be greater, and vice versa. Sc and K both have four energy levels, as can be shown. The difference between the two is that a neutral K atom has 19 protons and 19 electrons, but a neutral Sc atom has 21 protons and 21 electrons.
As a result, the attraction between positively charged protons and negatively charged electrons is stronger in Sc than in K. As a result, removing one electron will need more energy, which is why it has a higher initial ionisation energy. This corresponds to the rising ionisation energy as we travel right, as well as the pattern of ionisation energy increasing with period.
Hence Sc is the correct option

Note:
The energy necessary to remove electrons from gaseous atoms or ions is known as the ionisation energy of a chemical species (i.e., an atom or molecule). Ionization potential is another name for this characteristic, which is measured in volts. It is commonly used in chemistry to refer to one mole of a material (molar ionisation energy or enthalpy) and is expressed in kJ/mol. The ionisation energy is usually measured in electron volts in atomic physics (eV). The ionisation energy of large atoms or molecules is low, but the ionisation energy of tiny molecules is higher.