In this backward universe, hydrogen could not exist. Nor could there be any stable long-lived stars, which use hydrogen as nuclear fuel. Heavier elements such as carbon and oxygen, made in large stars, might never form either.
Without stable protons there could be no water and probably no biology. The universe would be very different. The fact that the universe we know, including our own existence within it, hinges so delicately on the precise value of the neutron-to-proton mass ratio has led to heated debate among scientists. Was it just a lucky fluke that the laws of physics turned out this way? Or does it suggest something more profound? Scientists are disinclined to believe in luck, so there has been a surge of interest in the multiverse theory, according to which our universe, with its neutron-to-proton mass ratio of 1.
Other universes will have different ratios and possibly only a tiny fraction will contain water and stars that go on to form atoms like carbon, from which life may arise. Only in that fraction could there be observers to ponder the fact. It is then no surprise that we find ourselves in a universe where the neutron mass is so judiciously poised to permit complex chemistry and our presence as thinking, observing beings. That seemed to be the case back in the s when the critical value of the mass ratio was first discussed.
However, we now know that neutrons and protons are not in fact elementary particles unlike the electron, which seems to be. Rather, they are composite bodies with smaller particles inside them. Known as quarks, these subnuclear constituents have their own masses. This structural complexity makes it nigh on impossible to work out accurate values for the masses of the proton and neutron by analysis of their constituents — let alone figure out what it would take for the mass contribution of this quark or that quark to shift enough to upset that crucial neutron-to-proton mass ratio.
How does particle physics explain fundamental forces? What are some common mistakes students make with particle physics? What is the Standard Model? What particles are formed by radioactive processes? What is a Hilbert space? Are all elementary particles indivisible?
What are all types of elementary particles? Most of the atom is empty space. The strong force and you The Higgs field gives mass to fundamental particles—the electrons, quarks and other building blocks that cannot be broken into smaller parts.
The rest comes from protons and neutrons, which get almost all their mass from the strong nuclear force. Electrons are much smaller in mass than protons, weighing only 9. As the atomic number of an element increases, so does the size of its nucleus and the number of electrons around it. The loss in an electron will consequently result in a change in atomic radii in comparison to the neutral atom of interest no charge. The loss of an electron means that there are now more protons than electrons in the atom, which is stated above.
With electrons on the surface, atoms repel one another when they come too close. Thus, electrons determine the space that an atom occupies. So all the atoms of a given element have the same energy levels because they have the same numbers of electrons and protons. For example all hydrogen atoms have the same energy levels. Experiments have shown that the first case is what happens: the increase in nuclear charge overcomes the repulsion between the additional electrons in the valence level.
Therefore, the size of atoms decreases as one moves across a period from left to right in the periodic table. Valence electrons are the highest energy electrons in an atom and are therefore the most reactive.
For this reason, elements with the same number of valence electrons tend to have similar chemical properties, since they tend to gain, lose, or share valence electrons in the same way. Why do Hydrogen and Helium only need 2 valence electrons to be happy? Becuase they only have the first ring that can only hold 2 valence electrons to be full. How many valence electrons do elements in Group 1, the Alkali Metals, have? The mass of a proton is times of an electron thus is quite higher than the mass of the electron.
Generally, the mass of an electron is 9. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure.
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