Question

Which of Al, Au, Br, Ca, Cs, F, H, He, Hg, I, K, Mg, Na, O, P, S, and Si glows in the dark

A) Br
B) Ca
C) Hg
D) Na

Answer 1

option a,Mercury (Hg) is the correct element that glows in the dark among the given options. Potassium (K) has the smallest ionization energy due to its position in the periodic table.

Step-by-step explanation:

The question concerns elements that glow in the dark, and among the options given (Br, Ca, Hg, Na), the correct answer is (c) Hg, which stands for mercury. Mercury can emit light after being energized, a phenomenon often utilized in fluorescent lamps. The fact that mercury vapor can be electrically excited to produce ultraviolet light, which in turn causes a phosphor coating on the inside of the lamp to glow, is the basic principle behind its luminescence.

To address the question about the element with the smallest ionization energy, the answer is (a) K, known as potassium. Ionization energy tends to decrease as we move down a group in the periodic table because the valence electrons are farther from the nucleus and experience more shielding from the inner electrons, making them easier to remove.