Question

Atomic mass 38 containing element 'A' has 18 neutron. Give electronic configuration and atomic number of 'A' ?

Answer 1

Answer:

atomic mass= protons + neutrons

38 =p + 18

38-18 =p

20 = p

protons = atomic Number

20 = atomic Number

Electronic conferiguation=2,8,8,2

Answer 2

The electronic configuration is 2,8,8,2 and atomic number is 20.

Atomic mass of element =38

Number of neutrons = 18

We know that in an element number of protons are equal to number of electrons. So atom is neutral in nature.

We also know that atomic number is calculated by number of protons as they are present in the nucleus of atom.

Atomic mass - neutrons = protons

So number of protons = 38-18 = 20.

Hence atomic number = 20.

Number of electrons are calculated by:-

Number of electrons = number of protons.

Number of electrons  = 20.

Electronic configuration is arrangement of how electrons are arranged in shells and subshells,

Electronic configuration by magic number in shells is 2, 8, 8, 2

Electronic configuration at subshell is given by aufbau that is  :--

Subshells--  1s^2, 2s^2, 2p^6,3s^2 3p^6, 4s^2.

So atomic number of element A is 20 and electronic configuration is 2, 8, 8, 2.