Answer: The electron arrangement for gallium is:
Ar 3d10 4s2 4p1
Answer:
30, 50
Explanation:
Hello,
In this since an element's atomic number is equal to the number of protons in its atom, we can infer that selenium's atomic number is 30. Moreover, due to the fact the the neutrons are equal to the atomic mass minus the atomic number or the number of protons, by knowing the number of neutrons we compute the atomic as follows:

Thus, answer is 30, 50.
Best regards.
1 ba+2 br——>1 babr2
u just have to make sure u have the same number of each type of atom on either side of the equation:)
The answer is <span>a total of eight valence electrons
hope this help
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