The quantum numbers for the outermost electron of an element are given as $n = 2, l = 0, m = 0, s = +\frac{1}{2}$. The element is

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:

When the $4d$ orbital is complete,the newly entering electron goes into which orbital?

The orbital angular momentum of an electron in $2s$ orbitals is

For $n = 5$ and $m = 2$,which of the following statements is incorrect?

The configuration $1s^2 2s^2 2p^5 3s^1$ shows