Question

sb fail hogey agr answer nhi diya to​

Answer 1

Answer of 1'st question is -

$1s {}^{1} \:$

Here is 2nd question

$fe = 1s {}^{2} 2s {}^{2} 2p {}^{6} 3s {}^{2} 3p {}^{6} \\ 4s {}^{2} 3d {}^{6} \\ for \: its \: 20th \: electron \\ n = 4 \\ l = 0\\ m = 0 \\ s = - \frac{1}{2}$

Hope this helps u , mark as brainliest