Write the outer electron configuration for the group 15 element in the fourth period.

4s² 4p³

Explanation:

1) To determine the outer electron configuration of an element you need to know the number of electrons and use Aufbau rules (or the energy levels of of the electrons).

2) The number of electrons of a neutral atom is equal to the number of protons.

3) The number of protons is the atomic number of the element.

4) The elements are arranged in the periodic table in attendance of the atomic number.

5) The elements in the group 15 are N, P, As, Sb, Bi, and Mc.

6) N is in the second period, P is in the third period, and As is in the fourtn period. So, your element is As.

7) The atomic number, number of protons, and number of electrons of As is 33.

8) Now you can distribute the electrons according to Aufbau rules:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p³

9) The outer shell is n = 4, so the outer electron configuration is 4s² 4p³

the correct answer is:

a. formation of precipitation

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