Structure of At...

Which among the following pairs of shells has the least energy difference between two adjacent orbits?

An atom has 2K, 8L and 5M electrons. Choose the correct statement(s) regarding it from the following:

A. Trivalent anion of this atom will have 12 protons in its nucleus.
B. Trivalent cation of this atom will have 6 p-electrons in it.
C. This atom forms an amphoteric oxide of formula X₂O₃.
D. One of its allotropes is tetraatomic (X₄).

If the N-shell is the outermost shell of the atom of an element, then what is the maximum number of electrons that it can accommodate?

Which of the following statements DO NOT match with the postulates of Bohr's model of atom?

(a) Electrons are revolving around the nucleus in specified paths called orbits/shells.
(b) Each shell is associated with definite amount of energy.
(c) Electron, while revolving through a particular shell, can increase or decrease its energy.
(d) Energy of the shells decreases as their distance from the nucleus increases.

When an electron in the M-shell of an atom gains energy, it moves to

Structures of nuclei of three atoms X, Y and Z are as follows:

(A) X has 90 protons and 146 neutrons.
(B) Y has 92 protons and 146 neutrons.
(C) Z has 90 protons and 148 neutrons.

Which of the following statements is correct based on the above data?

Which among the following shows the group of atoms having the same number of neutrons in their nuclei? [Given, the atomic masses of the elements Na, Mg, Al, Be, Ca, C, O and N are 23 u, 24 u, 27 u, 9 u, 40 u, 14 u, 16 u and 15 u, respectively]