We will see that the quantum numbers discussed in this section are valid for a broad range of particles and other systems, such as nuclei. Some quantum numbers, such as intrinsic spin, are related to fundamental classifications of subatomic particles, and they obey laws that will give us further insight into the substructure of matter and its interactions.
Phet explorations: stern-gerlach experiment
The classic Stern-Gerlach Experiment shows that atoms have a property called spin. Spin is a kind of intrinsic angular momentum, which has no classical counterpart. When the z-component of the spin is measured, one always gets one of two values: spin up or spin down.
Section summary
Quantum numbers are used to express the allowed values of quantized entities. The principal quantum number
$n$ labels the basic states of a system and is given by
where
$l$ is the angular momentum quantum number. The direction of angular momentum is quantized, in that its component along an axis defined by a magnetic field, called the
$z$ -axis is given by
where
${L}_{z}$ is the
$z$ -component of the angular momentum and
${m}_{l}$ is the angular momentum projection quantum number. Similarly, the electron’s intrinsic spin angular momentum
$S$ is given by
where
${S}_{z}$ is the
$z$ -component of spin angular momentum and
${m}_{s}$ is the spin projection quantum number. Spin projection
${m}_{s}\text{=+}1/2$ is referred to as spin up, whereas
${m}_{s}=-1/2$ is called spin down.
[link] summarizes the atomic quantum numbers and their allowed values.
Conceptual questions
Define the quantum numbers
$\mathrm{n,\; l,}\phantom{\rule{0.25em}{0ex}}{m}_{l}\mathrm{,\; s}$ , and
${m}_{s}$ .
For a given value of
$l$ , what are the allowed values of
${m}_{l}$ ? What are the allowed values of
${m}_{l}$ for a given value of
$n$ ? Give an example in each case.
(a) What is the magnitude of the angular momentum for an
$l=1$ electron? (b) Calculate the magnitude of the electron’s spin angular momentum. (c) What is the ratio of these angular momenta?
Propose a force standard different from the example of a stretched spring discussed in the text. Your standard must be capable of producing the same force repeatedly.
ok we can say body is electrically neutral ...conductor this quality is given to most metalls who have free electron in orbital d ...but human doesn't have ...so we re made from insulator or dielectric material ... furthermore, the menirals in our body like k, Fe , cu , zn
Abrar
when we face electric shock these elements work as a conductor that's why we got this shock
Abrar
how do i calculate the pressure on the base of a deposit if the deposit is moving with a linear aceleration