Which of the following is true ?

Options

A. According to pauli's exclasion principle ,no two electron in an atom can have the same value of quantum number n,l, and m
B. The total energy of an electron in an orbit is half of its potential energy
C. The speed of an electron in a orbit increases with increase of its quantum number n
D. The energy of an electron in a orbit decreases with increase of its quantum number n

Answer

B

Explanation

a . The correct statement is as under No two electrons in an atom can have the same value of all four quantum numberts n.l,m and m_(s)
b. The expressions are
`PE = - (Ze^(2))/((4 pi epsilon_(0))r)`
`E = KE + PE`
`= (1)/(2) (Ze^(2))/((4pi epsilon_(0))r) - (Ze^(2))/((4 pi epsilon_(0))r) = - (1)/(2) (Ze6(2))/((4 pi epsilon_(0))r)`
c. The expressions of valocity is `v= (1)/(n)` (constant)
d. The expressions of valocity is `E =- (1)/(n^(2))` (constant)