Question

Electromagnetic radiation of wavelength $242\;nm$ is just sufficient to ionise the sodium atom. Calculate the ionisation energy of sodium in $kJmo{l^{ - 1}}$.

Answer 1

Sodium has a symbol Na and has an atomic number of $11$ it is known to be a very reactive metal as it is a group $1$ element. All elements in group $1$ are highly reactive and as they donate electrons, they are called metals. They are highly malleable and good conductors of electricity. It does not occur as a free metal in nature but as a compound.

Complete step-by-step answer: Sodium is known to exist in various minerals such as rock salt and sodalite. Its salts are very highly water soluble and they have been leached by the process of water. By the electrolysis of sodium hydroxide, we can obtain sodium metal. Sodium is essential for both plants and animals which makes it a major cation in the extracellular fluid and its osmotic pressure and compartment volume.
Electromagnetic radiation occurs when photons flow. This can also be called light quanta that occur in space. They are called the packets of energy and this energy can be transferred in the form by the equation $E = Hv.$This always moves in the speed of light which is universal. Here $h$ is called as the Planck’s constant, where $h$ is the symbol of the same. And here $v$ is the same as the frequency of electromagnetic waves.
The ionization energy of sodium will be equal to the energy possessed by the radiation of wavelength $242\;nm$
It is $E = \frac{{hc}}{\lambda }\, = \frac{{6.626 \times {{10}^{ - 34}}Js \times 3 \times {{10}^8}}}{{242 \times {{10}^{ - 9}}m}} = 8.21 \times {10^{ - 19}}J$
The ionization energy per mole is $8.21 \times {10^{ - 19}} \times 6.023 \times {10^{23}} = 494000J = 494kJ.$

Note: The spectrum changes as per the frequencies of these electromagnetic radiation which can be the low values such as radio waves, television waves and microwaves to visible light which has higher values such as ultraviolet light and gamma rays. In nerve cells, the electrical charge across the cell membrane enables transmission of the nerve impulse—an action potential—when the charge is dissipated; sodium plays a key role in that activity.