- published: 20 Jan 2015
- views: 1478758
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons (except in the case of hydrogen-1, which is the only stable nuclide with no neutrons). The electrons of an atom are bound to the nucleus by the electromagnetic force. Likewise, a group of atoms can remain bound to each other, forming a molecule. An atom containing an equal number of protons and electrons is electrically neutral, otherwise it has a positive charge if there are fewer electrons (electron deficiency) or negative charge if there are more electrons (electron excess). A positively or negatively charged atom is known as an ion. An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determines the isotope of the element.
The name atom comes from the Greek ἄτομος (atomos, "indivisible") from ἀ- (a-, "not") and τέμνω (temnō, "I cut"), which means uncuttable, or indivisible, something that cannot be divided further. The concept of an atom as an indivisible component of matter was first proposed by early Indian and Greek philosophers. In the 17th and 18th centuries, chemists provided a physical basis for this idea by showing that certain substances could not be further broken down by chemical methods. During the late 19th and early 20th centuries, physicists discovered subatomic components and structure inside the atom, thereby demonstrating that the 'atom' was divisible. The principles of quantum mechanics were used to successfully model the atom.
Throw open all the doors
There’s a warm wind blowing through
Let the gifts of ages
Pour over you
Let it rise within you now
Let the shine light up your way
Chasing all your doubts and clouds
Far away
Every time it happens
Atoms scatter on the road ahead
So don’t look away, don’t let it stay
To other schemes instead
Don’t wait too long
Can’t you see that summer’s come
And this world that’s lipped it’s crown
It took some saving
There’s a sky of newest blue
Way beyond this burning sun
A clear and perfect view
On and on
Every time it happens
Atoms scatter on the road ahead
So don’t look away, don’t let it stay
To other schemes instead
Don’t wait too long
Can’t you see that summer’s come
And this world that’s lipped it’s crown
It took some saving
So don’t wait too long
Can’t you see that summer’s come
Every time it happens
Atoms scatter on the road ahead
So don’t look away, don’t let it stay
To other schemes instead
Don’t wait too long
Can’t you see that summer’s come
And this world that’s lipped it’s crown