Question

e. in the space below, write the full (unabbreviated) electron configurations of the following elements:

1. sodium
2. iron
3. bromine
4. barium
5. neptunium

f. in the space below, write the noble gas (abbreviated) electron configurations of the following elements:

1. cobalt
2. silver
3. tellurium
4. radium
5. lawrencium

g. determine what elements are denoted by the following electron configurations:

1. 1s²2s²2p⁶3s²3p⁴
2. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s¹
3. kr 5s²4d¹⁰5p³
4. xe 6s²4f¹⁴5d⁶
5. rn 7s²5f¹¹

Explanation:

Step1: Recall electron - filling rules

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

Step2: Write full electron configurations for E

1) Sodium (Na, atomic number = 11)

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

2) Iron (Fe, atomic number = 26)

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

3) Bromine (Br, atomic number = 35)

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

4) Barium (Ba, atomic number = 56)

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

5) Neptunium (Np, atomic number = 93)

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

Step3: Write noble - gas abbreviated electron configurations for F

6) Cobalt (Co, atomic number = 27)

$[Ar]3d^{7}4s^{2}$

7) Silver (Ag, atomic number = 47)

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

8) Tellurium (Te, atomic number = 52)

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

9) Radium (Ra, atomic number = 88)

$[Rn]7s^{2}$

10) Lawrencium (Lr, atomic number = 103)

$[Rn]5f^{14}6d^{1}7s^{2}$

Step4: Determine elements from electron configurations for G

11) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{4}$

Sulfur (S), since the total number of electrons is 2 + 2+6 + 2+4=16.

12) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{1}$

Rubidium (Rb), as the total number of electrons is 37.

13) $[Kr]5s^{2}4d^{10}5p^{3}$

Antimony (Sb), adding the 36 electrons from Kr to 2 + 10+3 = 41 electrons in the outer - shell gives atomic number 51.

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

Osmium (Os), with 54 electrons from Xe and 2+14 + 6=22 electrons in the outer - shell, atomic number 76.

15) $[Rn]7s^{2}5f^{11}$

Einsteinium (Es), 86 electrons from Rn and 2+11 = 13 electrons in the outer - shell, atomic number 99.

Answer:

1. $1s^{2}2s^{2}2p^{6}3s^{1}$
2. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{6}4s^{2}$
3. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{5}$
4. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^{6}6s^{2}$
5. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}4f^{14}5s^{2}5p^{6}5d^{10}5f^{4}6s^{2}6p^{6}6d^{1}7s^{2}$
6. $[Ar]3d^{7}4s^{2}$
7. $[Kr]4d^{10}5s^{1}$
8. $[Kr]4d^{10}5s^{2}5p^{4}$
9. $[Rn]7s^{2}$
10. $[Rn]5f^{14}6d^{1}7s^{2}$
11. Sulfur
12. Rubidium
13. Antimony
14. Osmium
15. Einsteinium