Calculate the wavelength (in nanometer) associated with a proton moving at 1.0 × 10³ ms^-1.(Mass of proton = 1.67 × 10^-27 kg and h = 6.63 × 10^-34 Js)

0.40 nm
2.5 nm
14.0 nm
0.32 nm

Solution

The total number of atomic orbitals in fourth energy level of an atom is :

Solution

Total no.of atomic orbitals in a shell = n².

Given n = 4; Hence number of atomic orbitals in 4^th shell will be 16.

Which of the following is not permissible arrangement of electrons in an atom?

n = 5, l = 3, m = 0, s = +1/2
n = 3, l = 2, m = –3, s = –1/2
n = 3, l = 2, m = –2, s = –1/2
n = 4, l = 0, m = 0, s = –1/2

Solution

m = –l to +l, through zero thus for l = 2, values of m will be – 2, –1, 0, +1, +2.Therefore for l = 2, m cannot have the value –3.

Maximum number of electrons in a subshell of an atom is determined by the following:

2l + 1
4l – 2
2n²
4l + 2

Solution

The number of sub shell is (2l + 1). The maximum number of electrons in the sub shell is 2(2l + 1) = (4l + 2)

The measurement of the electron position is associated with an uncertainty in momentum, which is equal to 1 × 10^–18 g cm s^–1.The uncertainty in electron velocity is, (mass of an electron is 9 × 10^–28 g)

1 × 10⁹ cm s^-1
1 × 10⁶ cm s^-1
1 × 10⁵ cm s^-1
1 × 10¹¹ cm s^-1

Solution

Δp = mΔv

Substituting the given values of Δx and m, we get

1 × 10^-18g cm s^-1 = 9 × 10^-28g × Δv

or \(\Delta v = \frac{1 \times 10^{-18}}{9 \times 10^{-28}}\)

= 1.1 × 10⁹cm s^-1 ≅ 1 × 10⁹ cm s^-1

i.e. option (a) is correct.

An element M has an atomic mass 19 and atomic number 9, its ion is represented by

M⁺
M²⁺
M^-
M^2-

Solution

Atomic number 9 is for F and ion is F^–.

The number of nodal planes ‘d’ orbital has

1
2
3
Zero

Solution

Number of nodal planes in d orbitals is 2.

An electron has principal quantum number 3. The number of its (i) subshells and (ii) orbitals would be respectively

3 and 5
3 and 7
3 and 9
2 and 5

The de Broglie wavelength associated with a ball of mass 200g and moving at a speed of 5 m/h, is of the order of (h = 6.625 × 10^–34Js)

10^–15 m
10^–20 m
10^–25 m
10^–30 m

Solution

Which of the following represents correct set of the four quantum numbers for an electron in a 4d subshell ?

4, 2, 1, 0
4, 2, 1, –1/2
4, 3, 2, +1/2
4, 3, –2, –1/2

Solution

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