Question

A) Write outer electron configuration of Cr atom. Why half - filled orbitals more stable?b) An electron has a velocity of 50 m/s accurate upto 99.99%. Calculate the uncertainty in locating its positions. (Mass of electron  = 9.1 X 10-31kg , h = 6.626 X 10-34Js)c) What is meant by i) Stark effect and ii) Zeeman effect?

Answer 1

A) extra stability is associated with atoms in which degenerating orbitals with are either half filled or fulfilled due to
1)symmetrical distribution of electrons and
2) Exchange energy
Greater the energy level ,greater is the stability.
The outer electronic configuration of chromium is [Ar]4s¹3d⁵
both d and s orbitals are half filled and posess greater exchange value hence greater stability.
B)
by using Heisenberg's equation:
(Δx)(Δv)=h/4πm
Δv=40m/s(99.99% accurate)
=(100-99.99)x40/100
4x10⁻3m/s
m=9.1x 10⁻34 kg
h=6.625 x 10⁻³⁴ kg m²s⁻¹
π=3.14
by substituting all these values in equation 1 , we get
Δx=6.625 x 10⁻³⁴ /4x3.14x9.1x 10⁻34x4x 10⁻³
=0.0144m
c)Stark effect:Splitting up of spectral line in an external electric field into fine lines
Zeeman effect: Splitting up of spectral line in an external magnetic field ibto fine line