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The complete photoelectron spectrum of an element is given above. Which of the following electron configurations is consistent with the spectrum?

A) 1s2 2s2 2p6 3s2 3p2
B) 1s2 2s2 2p6 3s2 3p3
C) 1s2 2s2 2p6 3s2 3p4
D) 1s2 2s2 2p6 3s2 3p5

1 Answer

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Final answer:

The question pertains to predicting an element's electron configuration based on its periodic table position and a given photoelectron spectrum. Electron configurations follow the energy order of orbitals and are notated according to the Aufbau principle. The configurations are often written in condensed form using the nearest noble gas shorthand.

Step-by-step explanation:

The question asks to predict the electron configuration of an element based on its position on the periodic table and to match it with a given photoelectron spectrum. Understanding the electron configuration of elements is a key topic in chemistry, particularly in the study of atomic structure and periodicity. The electron configuration of an element describes the arrangement of electrons in atomic orbitals, and it follows a specific order according to the Aufbau principle, with electrons filling the orbitals in order from lowest to highest energy.

For instance, the first two electrons fill the 1s orbital, leading to the configurations 1s¹ for hydrogen and 1s² for helium. Following this, electrons fill the 2s orbital (giving lithium the configuration [He]2s¹ and beryllium [He]2s²), and then the 2p orbitals. This trend continues, filling the 3s, 3p, and eventually the 4s orbital before moving on to the 3d orbitals, following the energy order of orbitals (1s<2s<2p<3s<3p<4s, etc.). The condensed electron configuration can simplify notation by using the nearest noble gas to represent already filled shells, as seen with magnesium ([Ne]3s²) and carbon ([He]2s² 2p²).

Comparing the electron configurations of elements within the same row of the periodic table can highlight similarities and differences in their chemical properties. For example, elements in the second row from boron to nitrogen have configurations incrementally increasing in p-electrons ([He]2s² 2p¹, [He]2s² 2p², [He]2s² 2p³ respectively).

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