Beryllium (Be)

Practice

Practice beryllium

Questions from the course about beryllium. If you’re signed in, your answers count toward your progress.

1. Question 1Energy levels of hydrogen-like ionsExam level

   What is the energy of the electron in the $n = 4$ level of a $\ce{Be^3+}$ ion, in kJ per mole? Include the sign. ($R_H = 2.179 \times 10^{-18}\ \mathrm{J}$, $N_A = 6.022 \times 10^{23}\ \mathrm{mol^{-1}}$)

   Your answer (in the unit shown)

   $\mathrm{kJ\,mol^{-1}}$

   Scientific notation: type 4.86e-7 or 4.86 x 10^-7.

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2. Question 2Ground-state electron configurationWarm-up

   Which is the ground-state electron configuration of a neutral beryllium atom ($\ce{Be}$)?

   A$1s^{2}\,2s^{1}$B$1s^{2}\,2s^{2}$C$1s^{2}\,2s^{2}\,2p^{2}$D$1s^{2}\,2s^{2}\,2p^{1}$

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3. Question 3Count unpaired electronsWarm-up

   How many unpaired electrons are there in a ground-state gaseous beryllium atom ($\ce{Be}$)?

   Your answer

   Whole number.

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