Question

electron configuration exercise
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.
the sum of the superscripts should equal the total number of electrons. example: 12mg 1s²2s²2p⁶3s²
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. rb
3. sr
4. u
5. n
6. ag
7. ti
8. ce
9. cl
10. hg

Explanation:

Step1: Determine number of electrons

For a neutral atom, the number of electrons is equal to the atomic number.

Step2: Apply Aufbau principle

Fill orbitals in order of increasing energy ($1s<2s < 2p<3s<3p<4s<3d<4p<5s<4d<5p<6s<4f<5d<6p<7s<5f<6d<7p$).

Step3: Write electron - configurations

1. Na (Sodium), atomic number = 11:

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

1. Rb (Rubidium), atomic number = 37:

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{1}$

1. Sr (Strontium), atomic number = 38:

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}$

1. U (Uranium), atomic number = 92:

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^{10}6p^{6}7s^{2}5f^{3}6d^{1}$

1. N (Nitrogen), atomic number = 7:

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

1. Ag (Silver), atomic number = 47:

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}4d^{10}5s^{1}$

1. Ti (Titanium), atomic number = 22:

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

1. Ce (Cerium), atomic number = 58:

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{1}5d^{1}$

1. Cl (Chlorine), atomic number = 17:

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

1. Hg (Mercury), atomic number = 80:

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^{10}$

Answer:

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