Question

what will be the composition of the nucleus of the atom of an element with atomic number 19 and mass number 39 ? also write the electronic configuration.

Answer 1

no. of nuleons=mass no.=no. of [p{+}] + [n^{0}]
gn. A=39
n^{0}=39-19=20
and p^{+}=19
Electronic config. = 2,8,9
also 1s^{2} , 2s^{2} , 2p^{6} , 3s^{2} , 3p^{6} , 4s^{1}

Answer 2

Answer : The element will be $_{19}^{39}\textrm{K}$ and the electronic configuration is given below.

Explanation :

The atomic number = 19

The atomic mass = 39

The composition of the nucleus of the atom of an element is, potassium.

As we know that the number of protons and the number of electrons is equal to the atomic number.

So, the number of electrons = 19

Thus, the electronic configuration of potassium is, $1s^22s^22p^63s^23p^64s^1$

Hence, the element will be $_{19}^{39}\textrm{K}$.