Identify the specific element it corresponds each the following electron configurations:
We have to make the assumption that these represent uncharged atoms (elements in the zero oxidation state).
I’ll do one to show you how to do it, then you can do the others yourself.
Step 1: count the total number of electrons:
1s2 => 2 electrons
2s2 => 2 electrons
Total electrons = 2 electrons + 2 electrons = 4 electrons
Step 2: for an element in the zero oxidation state, the atomic number (the number of protons) will be the same as the number of electrons, so this element has atomic number = 4
Step 3: look up in a periodic table what element has that atomic number:
In this case, it is beryllium, Be.
Now work the rest yourself. I’ll give you a hint for (d): for the [Kr] part of the electronic structure, look up Kr in the periodic chart and use its atomic number for its part of the total electron count.