Aluminum (Al) has an atomic number of 13 and an atomic mass of 27. Which of the following correctly shows the electron arrangement for aluminum?

2, 11
2, 8, 1
2, 8, 3
2, 8, 17

Question

Aluminum (Al) has an atomic number of 13 and an atomic mass of 27. Which of the following correctly shows the electron arrangement for aluminum?

2, 11
2, 8, 1
2, 8, 3
2, 8, 17

anonymous · Answer

what youre basically interested in here is the electron arrangement...

the answer is 2,8,3...

because the first energy level can only hold 2 electrons...the second level can hold 8 and the third can hold 8 ( though it can expand to hold 18...but thats not important now)...

anyways...the first holds 2...which leaves you with 11...the second holds 8 which then leaves you with 3....

hence the arrangement 2,8,3

preetha · Answer

RagingSq, you had better review electronic config.  You should be able to write the electronic configs of the first 10 elements cold.