Answer
See explanation
Work Step by Step
a. $1s^22s^22p^63s^2$
Total electrons:
$2+2+6+2=12$
Valence electrons: 2 (in the 3s orbital)
Element: Magnesium (Mg)
b. $1s^22s^22p^63s^23p^3$
Total electrons:
$2+2+6+2+3=15$
Valence electrons: 5 (in the 3s and 3p orbitals)
Element: Phosphorus (P)
c. $1s^22s^22p^63s^23p^64s^23d^{10}4p^65s^24d^2$
Total electrons:
$38$
Total electrons: 38
Valence electrons: 2 (in the 5s orbital) + 2 (in the 4d orbital) = 4
Element: Zirconium (Zr)
d. $[Ar] 4s^2 3d^6$
Total electrons:
[Ar] = 18 electrons
4s² = 2 electrons
3d⁶ = 6 electrons
Total = 18 + 2 + 6 = 26 electrons
Valence electrons = 2 (4s) + 6 (3d) = 8
Element:
Atomic number = 26
Iron (Fe)
