Question

question 10
identify the number of valence electrons of selenium
2
6
8
4
question 11
which of the following atoms is already or naturally in an octet electron configuration?
xenon
iodine
carbon
iron

Explanation:

Question 10

Selenium (Se) has an atomic number of 34. Its electron configuration is \([Ar]3d^{10}4s^{2}4p^{4}\). The valence electrons are in the \(n = 4\) shell (\(4s^{2}4p^{4}\)). The sum of electrons in these orbitals (\(2 + 4\)) gives the number of valence electrons.

• Xenon (\(Xe\)) is a noble gas. Noble gases have a full - outer shell (octet or more, but for the purpose of the octet rule, considering the valence shell). Xenon has 8 valence electrons in its valence shell (\(5s^{2}5p^{6}\)) and is in an octet electron configuration.
• Iodine (\(I\)) has 7 valence electrons (\([Kr]4d^{10}5s^{2}5p^{5}\)) and is not in an octet configuration.
• Carbon (\(C\)) has 4 valence electrons (\([He]2s^{2}2p^{2}\)) and is not in an octet configuration.
• Iron (\(Fe\)) has 2 or 3 valence electrons (depending on the oxidation state, but its electron configuration \([Ar]3d^{6}4s^{2}\) shows it does not have an octet in its valence shell).

Answer:

6

Question 11