Question

electron configuration practice
chemistry
how to write an electron configuration:
a. determine the total number of electrons to be represented.
b. use the aufbau principle to fill the orbitals with electrons for elements 1 - 23. refer to electron - configuration periodic table for elements after 23
c. the sum of the superscripts should equal the total number of electrons. example: 12mg 1s² 2s² 2p⁶ 3s²
i. configuration writing practice
a. write a ground state electron configuration for each neutral atom. ground state means that all of the lowest possible energy levels (up to the proper number of electrons for the element) are filled.

1. na:
2. pb:
3. sr:
4. u:
5. n:
6. ag:
7. ti:
8. ce:
9. cl:
10. hg:

Explanation:

Step1: Determine electrons for Na

Sodium (Na) has atomic number 11, so 11 electrons.

Step2: Fill orbitals using Aufbau principle

1s can hold 2 electrons, 2s can hold 2 electrons, 2p can hold 6 electrons and 3s can hold 2 electrons. We fill them in order: $1s^{2}2s^{2}2p^{6}3s^{1}$

Step3: Determine electrons for Pb

Lead (Pb) has atomic number 82.

Step4: Fill orbitals for Pb

$[Xe]4f^{14}5d^{10}6s^{2}6p^{2}$

Step5: Determine electrons for Sr

Strontium (Sr) has atomic number 38.

Step6: Fill orbitals for Sr

$[Kr]5s^{2}$

Step7: Determine electrons for U

Uranium (U) has atomic number 92.

Step8: Fill orbitals for U

$[Rn]5f^{3}6d^{1}7s^{2}$

Step9: Determine electrons for N

Nitrogen (N) has atomic number 7.

Step10: Fill orbitals for N

$1s^{2}2s^{2}2p^{3}$

Step11: Determine electrons for Ag

Silver (Ag) has atomic number 47.

Step12: Fill orbitals for Ag

$[Kr]4d^{10}5s^{1}$

Step13: Determine electrons for Ti

Titanium (Ti) has atomic number 22.

Step14: Fill orbitals for Ti

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{2}$

Step15: Determine electrons for Ce

Cerium (Ce) has atomic number 58.

Step16: Fill orbitals for Ce

$[Xe]4f^{1}5d^{1}6s^{2}$

Step17: Determine electrons for Cl

Chlorine (Cl) has atomic number 17.

Step18: Fill orbitals for Cl

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{5}$

Step19: Determine electrons for Hg

Mercury (Hg) has atomic number 80.

Step20: Fill orbitals for Hg

$[Xe]4f^{14}5d^{10}6s^{2}$

Answer:

1. $1s^{2}2s^{2}2p^{6}3s^{1}$
2. $[Xe]4f^{14}5d^{10}6s^{2}6p^{2}$
3. $[Kr]5s^{2}$
4. $[Rn]5f^{3}6d^{1}7s^{2}$
5. $1s^{2}2s^{2}2p^{3}$
6. $[Kr]4d^{10}5s^{1}$
7. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{2}$
8. $[Xe]4f^{1}5d^{1}6s^{2}$
9. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{5}$
10. $[Xe]4f^{14}5d^{10}6s^{2}$