Question

A certain atom has an [noble gas] 5s24d105p4 electron configuration. which element is it?

Answer 1

The electrons are arranged around the nucleus of an atom in an increasing order of energy levels and this description of orbitals of atom occupied by electrons is known as electronic configuration.

Electrons are distributed in the orbitals of the subshell. The specific region of space in which the movement of electrons are confined is said to be shells which are divided into subshells and are s-, p-, d-, and f-. Among these subshells, the electrons are grouped as orbitals.  

The number of electrons that these subshells can hold are:

s-block - 2

p-block - 6

d-block - 10

f-block - 14

The increasing order of energy of shells, subshell is shown in the image.

The given configuration is [noble gas]$5s^{2}4d^{10}5p^{4}$ that means the inner subshells are completely filled. So, the configuration will be:

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{4}$

The configuration of noble gas is:

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}$

This means that the atomic number of noble gas is 36. Since, element with atomic number 36 is krypton (noble gas) so, the noble gas is krypton, $Kr$.

The atomic number of element is $36 + 16 = 52$

Thus, element with atomic number 52 is tellurium, $Te$.

Hence, the element is  tellurium, $Te$.

Answer 2

The noble gas in the configuration is Krypton. The configuration belongs to Tellurium