The set of quantum numbers $n = 3$,$l = 0$,$m = 0$,$s = -1/2$ belongs to the element

Degenerate atomic orbitals have

Which of the following orbitals is impossible?

How many exchange pairs are possible for a $3d^5$ electronic configuration?

In a multielectron atom,which of the following orbitals described by three quantum numbers will have the same energy in the absence of electric and magnetic fields?
$A: n=1, \ell=0, m_{\ell}=0$
$B: n=2, \ell=0, m_{\ell}=0$
$C: n=2, \ell=1, m_{\ell}=1$
$D: n=3, \ell=2, m_{\ell}=1$
$E: n=3, \ell=2, m_{\ell}=0$
Choose the correct answer from the options given below:

Which of the following set of quantum numbers is correct for the $19^{th}$ electron of chromium?
$n$ $l$ $m$ $s$