By reacting, an element that does not have a complete set of valence electrons can acquire an electron configuration similar to that of a noble gas. why is a noble gas different from other elements? its highest electron-energy level is filled. it’s highest electron-energy level has one electron. it has a single electron-energy level. its highest electron-energy level is unoccupied.

Option (A) is correct.

A noble gas is different from other elements because its highest electron energy level is completely filled.The examples of noble gases are helium, neon, Argon , krypton,Xenon , radon.

All the noble gases have completely filled outermost shell. for example, Helium has two electrons and both of them are present in first shell. Neon has 10 electrons, so its electronic configuration is 2,8.It has two electrons in the first shell and eight electrons in the second shell. Thus the outermost shell of both Helium and Neon is completely filled.

This property of having completely filled outermost shells makes noble gases different from the rest of the elements.These noble gases are very less reactive .

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it