Question

k
shorthand: $1s^22s^22p^63s^23p^64s^2$
si
shorthand:
mn
shorthand:
zr
shorthand:

Explanation:

Step1: Find K's noble gas core

Potassium (K, atomic number 19) has the noble gas core of Argon (Ar, atomic number 18). The remaining electron is in the 4s orbital.

Step2: Write K's shorthand configuration

$[Ar]4s^1$

Step3: Find Si's noble gas core

Silicon (Si, atomic number 14) has the noble gas core of Neon (Ne, atomic number 10). The remaining 4 electrons fill $3s^23p^2$.

Step4: Write Si's shorthand configuration

$[Ne]3s^23p^2$

Step5: Find Mn's noble gas core

Manganese (Mn, atomic number 25) has the noble gas core of Argon (Ar, atomic number 18). The remaining 7 electrons fill $4s^23d^5$.

Step6: Write Mn's shorthand configuration

$[Ar]4s^23d^5$

Step7: Find Zr's noble gas core

Zirconium (Zr, atomic number 40) has the noble gas core of Krypton (Kr, atomic number 36). The remaining 4 electrons fill $5s^24d^2$.

Step8: Write Zr's shorthand configuration

$[Kr]5s^24d^2$

Answer:

• K: $[Ar]4s^1$
• Si: $[Ne]3s^23p^2$
• Mn: $[Ar]4s^23d^5$
• Zr: $[Kr]5s^24d^2$