Question

Number of completely filled orbitals in xenon atom (Xe) is:
a.) 17
b.) 18
c.) 27
d.) 28

Answer 1

Hint: Xenon is a chemical element having atomic number 54. Xenon is an inert gas which means that xenon has zero valence electrons. Valence electrons are the electrons which are present in the valence shell of the element.

Complete Solution :
- Xenon having atomic number 54 contains 54 electrons and 54 protons. Electrons revolve around the nucleus while protons are present in the nucleus along with the neutrons. The number of neutrons in xenon is 77. Neutrons are the neutral particles which means that they do not carry any charge while electrons and protons are charged particles. Electrons carry negative charge and proton carries positive charge.
- To solve this question first we have to understand the meaning of the term orbital. Orbitals refer to the dimensional motion of an electron around the nucleus in 3-D motion. The number of orbitals can be determined using the electronic configuration. Electronic configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbital. Since xenon is an inert gas, which means there will be no valence electrons.
Electronic configuration of xenon:
$$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}4d^{10}5s^{2}5p^6$$
There is one orbital in s subshell (l = 0), three orbitals in p subshell (l = 1) and similarly there are five orbitals in f subshell (l = 3).
Hence, there are 27 orbitals in the xenon atom.

So, the correct answer is “Option C”.

Note: Xenon is obtained commercially as a bi product during the separation of air into oxygen and nitrogen. It is 4.5 times heavier than earth's atmosphere, which is a mixture of a number of gaseous elements and compounds.