4.2B Review

Oxygen Electron Configuation

• $1s2s2p3s$

• $1s^12s^22p^23s^3$

• $1s^22s^22p^4$

• $1s^22s^23p^6$

Neon Electron Configuation

• $1s^22s^22p^4$

• $1s^12s^22p^2$

• $1s^22s^22s^6$

• $1s^22p^63d^2$

Sulfur Electron Configuration

•  $1s^22s^22p^63s^23p^4$  

•  $1s^12s^22p^23s^33p^33d^3$  

•  $1s^22s^22p^63s^23p^63d^{10}$  

•  $1s^22p^63d^8$  

Iron Electron Configuation

• $1s^22s^22p^63s^23p^63d^64s^2$

• $1s^22s^22p^63s^23p^63d^{10}$

• $1s^12s^22p^23s^33p^33d^34s^44p^44d^4$

• $1s^22s^22p^63s^23p^63d^{10}4s^2$

Answer explanation

REMEMBER: The last sublevel cannot have more than 8 electrons, so the previous sublevel "fills" early, leaving the 2 left for the next s-level.

Which element is this?

 $1s^22s^2$  

• Beryllium

• Boton

• Lithium

• Nitrogen

Which element is this?

 $1s^22s^22p^5$ 

• Fluorine

• Sodium

• Carbon

• Helium

Which element is this?

• Sodium

• Aluminum

• Magnesium

• Boron