People are composed of molecules, which are in turn composed of atoms. Each atom is mostly empty space, because the protons, neutrons, and electrons are extremely tiny, and the electrons are relatively distant from each other and from the nucleus. A scientist acknowledges that there is often a finite probability, however small, that a very unlikely event could happen. If all of each person's

Question

subatomic particles were aligned just right, they could move through the other person's empty atomic space. This is so unlikely as to be practically impossible, however.

What will be an ideal response?

Answer 1

Polar covalent bonds occur within a single molecule that shares electrons unequally; i.e., the constantly orbiting electrons spend more time at some locations and less at others. Nonpolar covalent bonds occur within a single molecule that shares electrons equally; i.e., the probability of an electron occupying a particular location is the same at all locations. Ionic bonds occur within a single molecule in which one atom completely loses an electron to another, causing each to develop an opposite charge; it is this electrical attraction that holds the molecule together.
Hydrogen bonding occurs between separate molecules that contain polar covalent bonds; where electrons spend more time the molecule is partially negative, and where electrons spend less time the molecule is partially positive. The ends of different molecules are thus electrically attracted to each other. Water is a polar covalent molecule, with the oxygen end being partially negative and attracted to the partially positive hydrogen portions of other water molecules. Hydrogen-bonding between water molecules is responsible for surface tension and the crystalline
structure of ice.