If an atom bomb in 1945 could destroy an entire city surely the atomic arsenal we now have is more than adequate to fulfill any military objective required of it.

The O atoms in each sheet are close packed and each Cr atom is surrounded by a distorted octahedron of O atoms.

Science is placing in our hands the ultimate power of the universe, the power of the atom.

And yet there is a note of hope, because this same science that is giving us the power of the atom is also giving us atomic vision.

We are looking inside the atom and seeing there a universe which is not material but something beyond the material, a universe that in a word is not matter but music.

And it is in this new vision of the atom that we find an affirmation and an invigoration of our faith.

To grasp our new view of the atom, we have to appreciate first of all how small the atom is.

So you see how small an atom is and how complicated you are.

Now although an atom is small, we can still in imagination have a look at it.

Since these electrons are moving like planets, you may wonder whether there is an atomic sun at the center of the atom.

Even if the atom were big enough to hold a football field, this nucleus is still only about the size of a pinhead.

And so today when we examine the structure of our knowledge of the atom and of the universe, we are forced to conclude that the best word to describe our universe is music.

`` If you substitute ' atom ' for ' angel ', the problem is not insoluble, given the metallic content of the pin in question ''.

Each carbon atom has 4 bonds ( either C-H or C-C bonds ), and each hydrogen atom is joined to a carbon atom ( H-C bonds ).

The species that gains the electron pair is the Lewis acid ; for example, the oxygen atom in H < sub > 3 </ sub > O < sup >+</ sup > gains a pair of electrons when one of the H — O bonds is broken and the electrons shared in the bond become localized on oxygen.

In chemistry and physics, the atomic number ( also known as the proton number ) is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus.

In an atom of neutral charge, the atomic number is also equal to the number of electrons.

The atomic number, Z, should not be confused with the mass number, A, which is the number of nucleons, the total number of protons and neutrons in the nucleus of an atom.

Protons and electrons bear opposite electrical charges which make them attract each other, and when they are joined they make up an atom of hydrogen -- the basic building block of matter.

Nevertheless, the basic idea of the atom was adopted by scientists thousands of years later because it elegantly explained new discoveries in the field of chemistry.

The atom is the basic unit of chemistry.

On the most basic level, electronegativity is determined by factors like the nuclear charge ( the more protons an atom has, the more " pull " it will have on negative electrons ) and the number / location of other electrons present in the atomic shells ( the more electrons an atom has, the farther from the nucleus the valence electrons will be, and as a result the less positive charge they will experience — both because of their increased distance from the nucleus, and because the other electrons in the lower energy core orbitals will act to shield the valence electrons from the positively charged nucleus ).

The term dipolar bond is used in organic chemistry for compounds such as amine oxides for which the electronic structure can be described in terms of the basic amine donating two electrons to an oxygen atom.

The basic principle that allows the device to operate is the fact that a caesium atom can exist in any of nine energy levels, which can be informally thought of as the placement of electron atomic orbitals around the atomic nucleus.

Some came up with the ad hoc claim that the basic unit was one-half of a hydrogen atom, but further discrepancies surfaced.

The Bohr model, in turn, was soon replaced by the Schrodinger model of the atom, as the basic atomic model used today.

An atom is a basic unit of matter consisting of a nucleus within a cloud of one or more electrons.

The hydrogen atom, as the basic building block of the universe, represents man's exploration of the physical world, his application of knowledge, and his development of technology.

This is the basic principle behind atom bombs and production of energy in nuclear reactors and stars ( like the Sun ).

Characteristic of non-nucleophilic bases is their steric bulk, which allows protons to attach to the basic atom but prevents alkyl groups from doing so.

In Lévi-Strauss ' order of things, the basic building block of kinship is not just the nuclear family, as in structural-functionalism, but the so-called kinship atom: the nuclear family together with the wife's brother.

One can talk of a unit for matter, like an atom or apple, and quantify how much potential and kinetic energy it has, but space and time have no unit-no identity.

The atomic mass unit, 1 gram divided by Avogadro's number, is almost the mass of a hydrogen atom, which is mostly the mass of the proton.

Allred and Rochow considered that electronegativity should be related to the charge experienced by an electron on the " surface " of an atom: the higher the charge per unit area of atomic surface, the greater the tendency of that atom to attract electrons.

A related early idea was Prout's hypothesis, formulated by English chemist William Prout, who proposed that the hydrogen atom was the fundamental atomic unit.

* The atomic mass unit ( u ) is defined so that a single carbon-12 atom has a mass of 12 u ; 1 u is approximately .< ref group =" note "> Since the Avogadro constant N < sub > A </ sub > is defined as the number of atoms in 12 g of carbon-12, it follows that 1 u is exactly 1 /( 10 < sup > 3 </ sup > N < sub > A </ sub >) kg .</ ref > The atomic mass unit is convenient for expressing the masses of atoms and molecules.

And in 1815, the chemist William Prout concluded that the hydrogen atom was in fact the fundamental mass unit from which all other atomic masses were derived.

In all these cases, a hydrogen atom and a hydroxyl (- OH ) group are lost to form H < sub > 2 </ sub > O, and an oxygen atom links each monomer unit.

In quantum mechanics, it refers to a discrete unit that quantum theory assigns to certain physical quantities, such as the energy of an atom at rest ( see Figure 1 ).

Each perovskite unit cell contains a Y or Ba atom at the center: Ba in the bottom unit cell, Y in the middle one, and Ba in the top unit cell.

The unit cell of these phases has double Bi – O planes which are stacked in a way that the Bi atom of one plane sits below the oxygen atom of the next consecutive plane.

Monotactic macromolecules have one stereoisomeric atom per repeat unit, ditactic to n-tactic macromolecules have more than one stereoisomeric atom per unit.

An atomic mass unit is, for roughly 40 atoms per cubic meter .</ ref > However, even if every single atom and particle could be removed from a volume, it would still not be " empty " due to vacuum fluctuations, dark energy, and other phenomena in quantum physics.

Since the standard unit for expressing the mass of molecules or atoms ( the dalton or atomic mass unit ) is defined as 1 / 12 of the mass of a < sup > 12 </ sup > C atom, it follows that the molar mass of a substance, measured in grams per mole, is exactly equal to its mean molecular or atomic mass, measured in daltons ; which is to say, to the substance's mean molecular or atomic weight.