Test: Structure of Atom - 3 - Grade 10 MCQ

Chadwick discovered the neutral particles known as neutrons.

The number of orbitals within an orbit is n2. But as each orbital can accommodate 2 electrons, the number of electrons that can exist with the “n” as the principal quantum number is 2n². So here 2n² = 2(4)² = 2(16) = 32.

Total number of nodes includes angular and radial nodes. Angular nodes and radial nodes are given by the formula n–l -1 and l respectively. So the total number of nodes is n–l -1+l = n–1. For 3d orbit, “n” is 3, so t total number of nodes is 3–1 = 2.

Radioactive elements are made up of atoms whose nuclei are unstable and give off atomic radiation as part of a process of attaining stability. The emission of radiation transforms radioactive atoms into another chemical element, which may be stable or maybe radioactive such that it undergoes further decay.

Elements that lose electrons show positive electrovalency and those which gain electrons show negative electrovalency. For example, in the formation of sodium chloride (Na⁺Cl^–), the electrovalency of sodium (Na) is +1, while that of chlorine (Cl) is –1.

Isotopes are members of a family of an element that all have the same number of protons but different numbers of neutrons. The number of protons in a nucleus determines the element's atomic number on the Periodic Table.

As per Aufbau's principle, the orbital or subshell with the lowest energy should be filled first. The ascending order of orbitals energy is given by 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 4f, 5d, 6p, 7s. So 2s orbital should be filled first.

Among the four quantum numbers, the principal quantum number describes the size and energy of the orbit. It is represented by the symbol “n”. For shells, K, L, M, N, and O, n are given by 1, 2, 3, 4, and 5.

Atoms of the same element which have the same atomic number but different mass number are called isotopes. So they have Similar chemicals but different physical properties.

Principal, Azimuthal and magnetic quantum numbers are respectively related to Size, shape and orientation.