Tiny Wonders / Atom

Tiny Wonders

What is an Atom?

 

ATOMS ARE THE VERY SMALL BITS or particles of the thing of which any substance is made. They are too small to be seen. Two billion atoms would fit on the dot that is on the top of this 'i'. Scientists earlier thought atoms were the tiniest things in the universe, like hard balls that could never be split or destroyed. But now, they know that atoms are more like clouds of energy, mostly empty space, containing even tinier sub-atomic' particles.

Inside an atom

At the center of every atom, there is a dense core or 'nucleus' having two kinds of tiny particles protons and neutrons. Around the nucleus, there are even tinier particles called electrons that move around at the speed of light.

Size of atoms

Atoms weigh about 100 trillionths of a trillionth of a gram and are about a ten-millionth of a millimeter big. The smallest atoms are the hydrogen atoms.

Helium nucleus

One of the smallest nuclei of an atom is that of an atom of helium. It combines two protons with two neutrons. However, it is not as small as that of hydrogen.

An Inside an atom

Atoms do not actually appear like this, but then it is a good way to consider them like this. Most of an atom is empty space, but there is a nucleus of protons and neutrons in the center, held together by special nuclear forces. The electrons move around the outer side, held firmly by the Opposite electrical charge on the protons.

Electrical charge

Protons attract electrons means they have a 'positive' electrical charge. Attract protons means they have a 'negative electrical charge. Neutrons do not have any charge. The number of protons and electrons in most atoms is the same which is why their charges balance out. The charge on electrons drives them apart. The electrons on an atom would fly off if they were not attracted to the protons.

Ion

An ion is a positively charged (cation) atom that has either lost one or more electrons, or a negatively charged (anion) atom that has gained one or a few electrons.

Covalent bond

Atoms are stable only when they have a full set of electrons in their outer shell. Atoms that have too many or too few electrons in their outer shell can get a full set by sharing electrons with other atoms. This sharing makes a covalent bond.

Ionic bond

Atoms are stable when they have a full set of electrons in their outer shells. They can get this by bonding with other atoms to make molecules. In an ionic' bond, One atom gives an electron to the other atom and becomes negatively charged. Thus the atoms are then bonded by mutual electrical attraction. That's how sodium atoms and chlorine atoms bond together to make salt molecules.

Molecules

Molecules are the smallest particles of a substance that can exist on their own. Those atoms that cannot exist by themselves join up with others either of the same kind or with another kind and form chemical compounds.
Kinds of sub-atomic particles

There are at least 200 kinds of sub-atomic particles, other than electrons, protons, and neutrons. But most sub-atomic particles are created in special conditions and exist only for a split second.

Smallest particles

Protons are made up of very small particles known as quarks. Electrons are also very small. But the smallest of all particles are known as neutrinos.