Question

A Gouy balance is used to determine the magnetic susceptibility of a substance. A strong electromagnet is placed next to the sample, which is on a balance. If the sample is paramagnetic, the mass reading of the balance will increase when the field is switched on. Based on their electron configurations, predict whether these elements are paramagnetic or diamagnetic.
Paramagnetic ...Diamagnetic
He ,Mg ,s ,Li

Answer 1

Answer:

Paramagnetic - S , Li

Diamagnetic - He , Mg

Explanation:

Paramagnetic are those which has unpaired electrons and diamagnetic are those in which all electrons are paired.

Given

He, the atomic number - 2

The electronic configuration is -  

$1s^2$

The electrons in 1s orbital = 2 (Paired)

Thus, the element is diamagnetic as the electrons are paired.

Mg, the atomic number - 12

The electronic configuration is -  

$1s^22s^22p^63s^2$

The electrons in 3s orbital = 2 (Paired)

Thus, the element is diamagnetic as the electrons are paired.

S, the atomic number - 16

The electronic configuration is -  

$1s^22s^22p^63s^23p^4$

The electrons in 3p orbital = 4 (Unpaired)

Thus, the element is paramagnetic as the electrons are unpaired.

Li, the atomic number - 3

The electronic configuration is -  

$1s^22s^1$

The electrons in 2s orbital = 1 (Unpaired)

Thus, the element is paramagnetic as the electrons are unpaired.