Why are some metals magnetic and some are not?

Answer 1

There is no necessary relationship between metals and magnets. Some metals and non-metals are attracted to magnets, while others aren't. Different materials have different characteristics, which vary not only depending on their elemental composition, but also their structure. Even frogs can be magnetized if you try hard enough.

Furthermore, the term "magnet" is not specific enough to answer this question. There are ferromagnetic materials, ferrimagnetic materials, paramagnetic materials, dimagnetic materials, electromagnets, etc, all of which work differently.

Answer 2

Each electron, in addition to having charge, also has a magnetic moment. Generally the bound electrons will be paired off in opposite spin pairs. This is like putting a North-South magnet next to a South-North magnet. They almost completely cancel each other out. However, sometimes there are one or more unpaired electrons. The magnetic fields of these electrons aren't canceled out by another, oppositely-oriented, electron. As such they lend an overall magnetic field to the atom they inhabit.

So, some metals are attracted to magnets because they are full of tinier magnets. Those tinier magnets twist about so that they align with the field of the larger magnet.

Answer 3

The complete answer to this question involves a deep understanding of quantum mechanics and electromagnetic theory, and is quite difficult to explain. Fortunately, there is an easier way, albeit not 100% accurate, that will guide you in the right direction.

All un-ionized atoms at rest have a certain number of protons, having +1 charge each, in the nucleus. The net positive charge from all of the protons creates an electric field surrounding the nucleus which attracts negative charges and repels positive charges. The act of attracting and repelling other charges toward and away from the nucleus requires the protons to use energy, so were this attraction and repellent behavior to continue on indefinitely, the protons would have to keep using energy indefinitely. However, were the protons able to reach an electrically neutral state of equilibrium with another particle, they wouldn't have to keep spending all that energy. Well, those particles do exist, they're called electrons, and sure enough, they and the protons do reach an electrically neutral state of equilibrium by bonding with each other in an equal quantity.

The above wall of descriptive text was a set up, since I'm pretty sure you know that electrons are in atoms, but you should pay attention to a subtle, yet very important idea that I used. There were two states described above, one with no electrons and one with an equal amount of electrons and protons, we'll call them state 1 and state 2 respectively. The system ended up choosing state 2 over state 1, but why? The answer is, as it is so often, energy. State 2, as was explained above, required the overall use of less energy than state 1. We call states like state 2 energetically favorable as opposed to state 1 which was energetically unstable, or simply unstable. Now for the part that would have driven Van Gogh crazy enough to slice off his other ear: The system in state 1 knew that state 2 existed before ever even noticing an electron. In fact, state 1 was doing everything it could possibly do to get to the lower energy state regardless of whether or not it was even feasible; it only cared that it was possible. This might not seem like a big deal, but in fact, it's the reason why EVERYTHING happens. All phenomena that is observable in the universe are only observable because of systems trying to get to a lower energy state, regardless of whether or not it will ever find the means.

This is why some metals aren't attracted to magnets. Those particular metals have reached a state of energy so low already, that the magnet doesn't have the strength to pull them out of it. Now, the way they reached this state is a bit complicated and weird, so I'm not going to go too in depth. Basically, there are shells (think of concentric spherical surfaces existing further and further away from the nucleus) of allowed energy states surrounding the nucleus that electrons are able to populate. Mind you, from quantum mechanics, the electrons can only be in these shells, not between them. Each shell has a maximum number of electrons that are allowed to be in them. Additionally, the most energetically favorable state for the atom would be if it had the exact amount of electrons to fill up one of the shells, no more no less. As discussed before, the atom is going to do whatever it can to get to that point, and, once it's there, try its hardest not to leave. That's the reason why some metals don't magnetize, for to do so, would mean leaving there stable state.

Bismuth, gold, lead, Mercury, silver and copper are examples of metals with most, if not all, of their shells closed. Not surprisingly then, they are also examples of metals that don't magnetize.

Lastly, it's important to remember that I'm using a modelto describe experimental results. There are no actual physical shells inside an atom, it just helps to think of it that way.

Answer 4

Ferromagnetic metals are attracted to magnets because they have a single electron (instead of two) in one of their inner orbitals, this makes each atom a tiny magnet. Nonferromagnetic metals have all the inner orbitals filled with two electrons.

Answer 5

Many particles have nonzero "intrinsic" (or "spin") magnetic moments. Just as each particle, by its nature, has a certain mass and charge, each has a certain magnetic moment, possibly zero. In magnetic materials, sources of magnetization are the electrons' orbital angular motion around the nucleus, and the electrons' intrinsic magnetic moment.

Ordinarily, the enormous number of electrons in a material are arranged such that their magnetic moments cancel out. This is due, to some extent, to electrons combining into pairs with opposite intrinsic magnetic moments as a result of the Pauli exclusion principle, or combining into filled subshells with zero net orbital motion. In both cases, the electron arrangement is so as to exactly cancel the magnetic moments from each electron. Moreover, even when the electron configuration is such that there are unpaired electrons and/or non-filled subshells, it is often the case that the various electrons in the solid will contribute magnetic moments that point in different, random directions, so that the material will not be magnetic.

However, sometimes - either spontaneously, or owing to an applied external magnetic field - each of the electron magnetic moments will be, on average, lined up. Then the material can produce a net total magnetic field, which can potentially be quite strong. The magnetic behavior of a material depends on its structure, particularly its electron configuration, for the reasons mentioned above, and also on the temperature.

The most common type of magnets are the "ferromagnets" so named because they include iron and iron tends to be attracted to them. A ferromagnet has unpaired electrons. However, in addition to the electrons' intrinsic magnetic moment's tendency to be parallel to an applied field, there is also in these materials a tendency for these magnetic moments to orient parallel to each other to maintain a lowered-energy state. Thus, even when the applied field is removed, the electrons in the material maintain a parallel orientation. Some well-known ferromagnetic materials that exhibit easily detectable magnetic properties (to form magnets) are nickel, iron, cobalt, gadolinium and their alloys.

Magnets work on some metals to attract them by inducing alignment of the electrons in the affected metal. This is called paramagnetism. Once the external magnetic field is removed, the alignments return to random rather than aligned. Some metals are much more susceptible to this kind of induced magnetic alignment than others. The electron configurations of the different metals are not the same - paired and unpaired electrons - orbitals filled and unfilled - higher and lower excitation levels - etc. Substances that are negligibly affected by magnetic fields are known as non-magnetic substances. The table below shows the comparative susceptibility of different materials to inducing a magnetic field. To be attracted to a magnet, a material needs to have a "relative permeability" greater than 1. Relative permeability, sometimes denoted by the symbol μ, is the ratio of the permeability of a specific medium to the permeability of free space.

Relative permeability (µ/µ0) data for selected materialsSuperconductors0Bismuth0.999834Water0.999992Copper0.999994Sapphire0.99999976Teflon1.0000Hydrogen1.0000000Air1.00000037Wood1.00000043Aluminum1.000022Platinum1.000265Neodymium magnet1.05Steel100Nickel100 - 600Ferrite (nickel zinc)16-640Concrete1Vacuum1Electrical steel4,000Mu-metal50,000Ferrite (manganese zinc)640 (or more)Permalloy8,000

Notice that there are significant differences between the different materials with some metals being very "magnetic" and others being about as magnetic as empty vacuum.

Answer 6

Actually, some metals are, others not so much. I believe there is always SOME attraction, but some metals (said to be "ferromagnetic") react more strongly than others who are not ferromagnetic.

Answer 7

Because the chemical structures of the atoms of different metals are not opposite and different metals have different charges.