posted by Meg on .
Give the symbol of the element of lowest atomic number whose ground state has:
a) Four f electrons
b) a completed d subshell
c) six s electrons
I don't understand ground state electrons at all? Could you explain them in addition to explaining the questions
Let's use an example. The electron configuration for carbon is
1s2 2s2 2p2. That is the ground state meaning that all of the lowest levels have been filled. If we want an excited atom, we might promote one of the 2p2 electrons up to a 3s and the configuration would be
1s2 2s2 2p1 3s1. That is NOT the ground state because the 3s electron can occupy a lower level; namely, the 2p level.
To answer these questions, you need to go to www.webelements.com and click on some of the elements (then scroll down to the "electron shell properties". Some hints:
a) The first f subshells to be filled start at 58.
b)There is a 3d and a 4d and 5d subshell. You may as well pick the smaller number. The 3d series starts at element 21.
c)I think Mg is the first element with 6 s electrons. Mg is #12 so it will be
1s2 2s2 2p6 3s2 gives the 6 s electrons. Actually, any element above Mg will have at least 6 (those past K will have more than 6) s electrons.