Test: Structure of Atom - 2 - Grade 10 MCQ

The azimuthal quantum number is given by “l”. When l =0, 1, 2, and 3, they are s-orbital, p-orbital, d-orbital, and f-orbital respectively. The shapes of s-orbital, p-orbital, d-orbital, and f-orbital are Spherical, Dumbbell, Double dumbbell, and Complex respectively.

Yes, no two electrons have the same set of all four quantum numbers. This is explained by Pauli’s exclusion principle. At most electrons can have all 3 quantum numbers the same as they are in the same orbital. But the spin quantum number’s values are different.

An element's valence is the number of hydrogen atoms that can combine with or replace (directly or indirectly) one of the element's atoms. Oxygen, for instance, has six valence electrons but its valence is 2. Some elements may have more than one power combination (or valence), while others may have only one.

Alpha particle consists of two neutrons and two protons and is thus identical to the nucleus of a helium atom. It has no charge. The mass of the particle is approximately the sum of the mass of the proton and neutron. Its charge is equal to that of 2 protons.

J.J Thomson discovered electrons in 1897 by performing the cathode ray experiment. Electrons are the smallest of the particles that make up an atom, and they carry a negative charge. The number of protons and electrons is equal in a neutral atom.

The charge to mass ratio (e/m) for the following is as follows –

• neutron, n = (0/1) = 0
• α− particle = (2/4) = 0.5
• Proton, p = (1/1) = 1
• Electron, p = (1/1837) = 1837.

The magnetic quantum number signifies the orientation of orbitals

As it is in M shell, n = 3

Number of electrons in M shell = 13 → 3s²3p⁶3d⁵

The electronic configuration is (1s²) (2s² 2p⁶) (3s² 3p⁶ 3d⁵) (4s¹)

The element is therefore chromium.

The energy required when an electron shifts from n = 1 to n = 2

E₂ = −(1.312 × 10⁶ × (1)²)/(2²) = −3.28 × 10⁵ J mol^-1

E₁ = −1.312 × 10⁶ J mol^-1

ΔE = E₂ − E₁

= −3.28 × 10⁵−(−13.2 × 10⁶)

ΔE = 9.84 × 10⁵ J mol^-1

In the Bohr model, the kinetic energy of an electron in an orbit = + (1/2) (e²/rn)

Total energy of the electron in an orbit = -(e²/2r_n)

Therefore, KE/TE = -1