IB Chemistry SL 1.3 Electron Configurations Questions

Practise IB Chemistry SL 1.3 by reading line spectra, tracing hydrogen transitions between energy levels and using orbital shapes and filling rules to build electron configurations.

Exam points

Compare line and continuous spectra, linking emitted or absorbed lines to electron transitions.
Read hydrogen lines to assign transitions to n=1/2/3, compare energies and explain convergence.
Calculate maximum electron capacity with 2n² from the principal quantum number n.
Sketch spherical s and dumbbell p orbitals, showing the p-orbital node and orientation.
Write atom and ion configurations to Z=36, including Cr/Cu exceptions and 4s electron loss.
Apply Aufbau, Hund and Pauli rules in orbital boxes to infer pairing and para-/diamagnetism.
Calculate photon energy or wavelength from spectral data using E=hf and c=fλ.

Covered syllabus points

1.3.1—Emission spectra 1.3.2—Hydrogen emission spectrum 1.3.3—Main energy levels 1.3.4—Sublevels 1.3.5—Orbitals and electron spin

[Maximum number: 8]

Lithium and boron are elements in period 2 of the periodic table. Lithium occurs in group 1 (the alkali metals) and boron occurs in group 3. Isotopes exist for both elements.

(a)

Deduce the electron arrangements of the lithium ion, $\mathrm{Li}^{+}$ , and the boron atom, B .
$\mathrm{Li}^{+}$ :
B:

[ 2 ]

$\mathrm{Li}^{+}: 2 / 1 \mathrm{~s}^{2}$ ;
$B: 2,3 / 1 \mathrm{~s}^{2} 2 \mathrm{~s}^{2} 2 \mathrm{p}^{1}$ ;

(b)

Every element has its own unique line emission spectrum.

[ 6 ]

(i)

Distinguish between a continuous spectrum and a line spectrum.

[ 2 ]

(ii)

Draw a diagram to show the electron transitions between energy levels in a hydrogen atom that are responsible for the two series of lines in the ultraviolet and visible regions of the spectrum. Label your diagram to show three transitions for each series.

[ 4 ]

[Maximum number: 1]

What is the maximum number of electrons that can occupy the n=3 main energy level?

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Covered syllabus points

Question 1

Question (a)

Question (b)

Question (i)

Question (ii)

Question 2