Question

2.06 electron configuration practice worksheet
in the space below, write the longhand electron configurations of the following elements:

1. carbon
2. tin
3. chlorine
4. cadmium
5. potassium

in the space below, write the shorthand electron configurations of the following elements:

1. radium
2. gold
3. vanadium
4. bromine
5. cesium

determine what elements are denoted by the following electron configurations:

1. 1s²2s²2p⁶3s²3p⁴ sulfur
2. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s¹ rubidium
3. kr 5s²4d¹⁰5p³ antimony
4. xe 6s²
5. rn 7s²

determine which of the following electron configurations are not valid:

1. 1s²2s²2p⁶3s²3p⁶4s²4d¹⁰4p⁵ not
2. 1s²2s²2p⁶3s³3d⁵ not
3. ra 7s² not
4. kr 5s²4d¹⁰5p⁵ valid

Explanation:

Step1: Recall electron - filling rules

Use Aufbau principle, Pauli - exclusion principle and Hund's rule to write electron configurations.

Step2: Write long - hand electron configurations

1) Carbon (C, atomic number = 6)

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

2) Tin (Sn, atomic number = 50)

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

3) Chlorine (Cl, atomic number = 17)

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

4) Cadmium (Cd, atomic number = 48)

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

5) Potassium (K, atomic number = 19)

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

Step3: Write shorthand electron configurations

6) Radium (Ra, atomic number = 88)

$[Rn]7s^{2}$

7) Gold (Au, atomic number = 79)

$[Xe]4f^{14}5d^{10}6s^{1}$

8) Vanadium (V, atomic number = 23)

$[Ar]3d^{3}4s^{2}$

9) Bromine (Br, atomic number = 35)

$[Ar]4s^{2}3d^{10}4p^{5}$

10) Cesium (Cs, atomic number = 55)

$[Xe]6s^{1}$

Step4: Identify elements from electron configurations

14) $[Xe]6s^{2}$ is Barium (Ba)

15) $[Rn]7s^{2}$ is Radium (Ra)

Answer:

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