Which of the following is the electron configuration for an electrically neutral atom of beryllium(Be)?
1s^2 2s^2

1s2^2s2^2p^6

1s^22s^22p^4

1s^22s^22p^44d^2

Question

Which of the following is the electron configuration for an electrically neutral atom of beryllium(Be)? 
        1s^2 2s^2

1s2^2s2^2p^6

1s^22s^22p^4

1s^22s^22p^44d^2

abb0t · Answer

[He]2s$^2$

preetha · Answer

Shamil, I hope you have your periodic table in front of you...

shamil98 · Answer

Yeah, in a new tab.

abb0t · Answer

[He] is the electron configuration for Helium, 1s$^2$

abb0t · Answer

Rember that s-orbital can fill maximum of 2 electrons, e$^-$.

shamil98 · Answer

Well , i think I've gotten the answer 2s^2. So would it be A?

preetha · Answer

1. Find the element in the periodic table
2. Look at the group number.  That is the number of outer valence electrons.
3. Be in is in II, so 2 valence electrons.  
4. In the list above, only two choices with 2 electrons.  1 and 4.  But 4 has d electrons.  Does Be have an outer electronic config with d electrons?  Therefore....

shamil98 · Answer

A is the answer.