Question

Which of the following sets of elements have the same number of electrons in outermost shell?

• A. Elements with atomic numbers 30,48, 80
• B. Elements with atomic numbers 14,15,16
• C. Elements with atomic numbers 20,30,50
• D. Elements with atomic numbers 10,18, 26

Answer 1

Answer: (A)

Elements with atomic numbers 30,48, 80

Elements with atomic numbers 30,48, 80 have the same number (two) of electrons in the outermost shell.

Element with atomic number 30 ; $\left[Ar\right]3d^{10}4s^2$ has two electrons in outermost shell.

Element with atomic number 48; $\left[Kr\right]4d^{10}5s^2$ has two electrons in outermost shell.

Element with atomic number 80; $\left[Xe\right]4f^{14}5d^{10}6s^2$ has two electrons in outermost shell.