Question

Speech on ionization enthalpy

Answer 1

Periodic trends for ionization energy (Ei) vs. atomic number: note that within each of the seven periods the Ei(colored circles) of an element begins at a minimum for the first column of the periodic table (the alkali metals), and progresses to a maximum for the last column (the noble gases) which are indicated by vertical lines and labelled with a noble gas element symbol, and which also serve as lines dividing the 7 periods. Note that the maximum ionization energy for each row diminishes as one progresses from row 1 to row 7 in a given column, due to the increasing distance of the outer electron shell from the nucleus as inner shells are added.

The ionization energy (British spelling: ionisation energy) (Ei) is qualitatively defined as the minimum amount of energy required to remove the most loosely bound electron, the valence electron, of an isolated neutral gaseous atom, molecule or ion. It is quantitatively expressed in symbols as

X + energy → X+ + e−

where X is any atom, molecule or ion capable of being ionized, X+ is that atom or molecule with an electron removed, and e− is the removed electron. This is generally an endothermic process.

Generally, the closer the electrons are to the nucleus of the atom, the higher the atom's ionization energy.

The units for ionization energy are different in physics and chemistry. In physics, the unit is the amount of energy required to remove a single electron from a single atom or molecule: expressed as an electron volt. In chemistry, the units are the amount of energy it takes for all of the atoms in a mole of substance to lose one electron each: molarionization energy or enthalpy, expressed as kilojoules per mole (kJ/mol) or kilocaloriesper mole (kcal/mol)