Just wondering, are atoms always spherical in shape?
“Shape” and “atom” don’t go together as we understand “shape” on the macro level. Atoms are “atom shaped”, and this can be described in many ways. For example, an “electron cloud” model of an atom emphasizes the uncertainty of the position of electrons at any given moment, so it looks like a “misty sphere”, with the “mist”–a representation of possible locations for an electron of that atom being “thicker” in the areas of the “orbital shells”.
Very few atoms are spherical. The electrons of an atom tend to orbit around a “nucleus” of positive and neutral charged particles. The shape of the “atom” depends on the energy level of the electrons. The orbit can be spherical, but is more commonly dumbbell, ring shaped or a dizzying combination of weird shapes. Try doing a google search for “electron cloud shape” or “p orbitals” or somesuch.
Most nuclei are prolate spheroids, like little footballs. This nonsphericity of charge must effect the symmetry of the electron shells, but that’s pretty tough to nail down experimentally. Electron orbitals take on some pretty wild, nonspherical shapes.
I formulated that question badly. I knew that there aren’t orbital paths as commonly shown in models but that they travel in a cloud. I was asking whether the nucleus of an atom is spherical since they are always depicted as little balls in atomic models.
A better question would be; Are electrons, positrons, and neutrons spherical?
Electron orbitals can have all sorts of odd shapes, but they’re more probailty distributions than solid shapes.
A common model used to describe the nucleus is the *liquid drop model’, formulated by the Niels Bohr. In the liquid drop model nuclei are thought of as a (usually) spherical ‘drop of liquid’ with interactions between nucleons manifesting themselves as ‘surface tension’. When this ‘drop’ is given sufficent energy it may deform into a non-spherical shape.
Electron orbitals indeed have all sorts of odd shapes, but in any atom that is not part of a molecule, and is not subject to sufficiently strong electric or magnetic fields, electrons will exist in a superposition of states in which they are present equally in orbitals of all possible spatial orientations.
Theory tells us that every atom in isolation is a perfect sphere.
The short answer is that we have no idea. Electrons are elemetary particles (can’t be broken down any further). Protons (you don’t mean positrons) are made up for 2 “up quarks” and 1 “down quark”. Neutrons are made up of 2 “down quarks” and 1 “up quark”.
The electical and nuclear forces are spherically symetrical, so one would expect the “shape” of atoms (in as much as they have shape) to be more or less spherical.
Holy Flurkin’ shnitt!! Those are actually images of atoms? I didn’t know they could do that yet.
After taking another look I must admit I don’t really understand what I’m looking at. In the first picture, am I looking at electron shells? And if so, how can you see a whole shell? Can’t the electron only be in a single place at any given time within the shell? Isn’t a shell really just the set of all points that an electron can possibly be, though each with varying probabilities?
And where’s the nucleus? Inside these spikes at the surface of the nickel crystal?
Strictly speaking you are seeing a representation of the probability of finding a tunneling electron at some distance from the surface as the probe of a scanning tunneling microscope moves horizontally across the surface. It is a representation that is made by using the tunneling current in the probe as described in the cite to vary the intensisty of a CRT beam or some such equivalent method.
The electrons surrounding the nucleus don’t “have” location. Essentially they are spread out into matter waves. They have many locations at the same time. As long as you don’t try to stop an electron and pin down its location, that single electron fills the volume of the shell. One electron really “is” the electron shell.
Light is similar: you can experiment with light waves, yet if you try to reach out and catch the light, you don’t find any waves, you just get individual photons… yet just one photon can behave like a light wave of ANY size.
About the nucleus: most atoms are about a fraction of a nanometer across, while their nuclei are tens or hundreds of thousands of times smaller. The “size of the atom” is the size of the outer electron shells, and when something pushes on an atom, it pushes on the electron shells. So, imagine that an atom is like a fuzzy misshapen golf ball made of electron-stuff, and the nucleus is a microscopic but extremely heavy dust mote in the center.