Question

Number of electrons in 21Sc with L=1​

Answer 1

There are
`12` electrons with
`l = 1` in each
`\rm _(21)Sc` atom in its ground state.

Step-by-step explanation:

The azimuthal quantum number (with symbol
`l`) of an electron in an atom specifies the type of the orbital that contains this electron.

For example:

• 
  `l = 0` corresponds to an
  `s` orbital.
• 
  `l = 1` corresponds to a
  `p` orbital.
• 
  `l = 2` corresponds to a
  `d` orbital.

The question is asking for the number of electrons with
`l = 1` in each
`\rm _(21)Sc` atom. Because
`l = 1\!` corresponds to
`p` orbitals, this question is equivalently asking for the number of electrons in
`p\!` orbitals in one such atom.

Find the electron configuration of a ground-state
`\rm _(21)Sc` atom:

`1s^(2)\; 2s^(2)\; 2p^(6)\; 3\, s^(2)\; 3\, p^(6)\; 3d^(1)\; 4s^(2)`.

In other words, there are
`12` electrons in
`p` orbitals in total in a ground-state
`\rm _(21)Sc` atom in total;
`l = 1` for each of these electrons because of the

Therefore, a ground-state
`\rm _(21)Sc` atom would include
`12` electrons with
`l = 1`.