Europium(II) oxide is a semiconductor with a band gap of 108 kJ/mol. Below 69 K, it is also ferromagnetic, meaning all the unpaired electrons on europium are aligned in the same direction. How many f electrons are present on each europium ion in EuO? (In lanthanide ions the 4f orbitals are lower in energy than the 6s orbitals.)

Video transcript

Hello. Everyone in this video being asked how many electrons are there and then lengthen them three plus ion are being told that the four D orbital is lower in energy than the six S orbital. So lengthen um has an atomic number of 57. So this comes after Xenon and our payroll table like the number of the D block elements. So the electron configuration equation is going to be n S two N -1 DXRN. Here represents the period number and our X here represents the number of electrons in the D orbital. So lengthen them is in the first column of the D block. So our X then is equal to one and the closest noble gas is going to be Xenon in that case the noble gas configuration for lengthen and its neutral state is X E six S two and five D one. Now for lengthen on three plus ion, we removed the electrons in the six S. And the five D sub shell. So the noble gas configuration for this is going to be just our X E. We completely removed R six S two and five D one electrons. So then they fought before diesel shell is completely filled before we reach Arizona in the pr table. So this means to answer the question then, is that there are 10 d electrons in our lengthen um three plus ion. So this right here is going to be my final answer for this question. Thank you all so much for watching