Question

Write the number of protons, neutrons, and electronic configuration of ${}^{39}{}_{19}K,{}^{31}{}_{15}P.$ Also, state their position in the periodic table.

Answer 1

The number of protons, neutrons, and electronic configuration of ${}^{39}{}_{19}K$:

• The atomic number and atomic mass of K are 19 and 39, respectively.
• Since atomic number=number of protons= number of electrons. Therefore, the number of protons in K is 19.
• The number of neutrons is calculated as (number of neutrons)=(mass number)-(atomic number).

Hence, the number of neutrons in K is
(39-19)=20.

• The electronic configuration of K is 2, 8, 8, 1.
• Since potassium (K) has 4 shells and 1 valence electron. Hence, it is placed in the $4^{th}$ period and $1^{st}$ group in the periodic table.

The number of protons, neutrons, and
electronic configuration of ${}^{31}{}_{15}P$:

• The atomic number and atomic mass of P are 15 and 31 respectively.
• Since atomic number=number of protons= number of electrons. Therefore, the number of protons in P is 15.
• The number of neutrons is calculated as (number of neutrons)=(mass number)-(atomic number).

Hence, the number of neutrons in P is
(31-15)=16.

• The electronic configuration of P (phosphorous) is 2, 8, 5.
• Since phosphorus (P) has 3 shells and 5 valence electrons. Hence, it is placed in the $3^{rd}$ period and ${15}^{th}$ group in the periodic table.