Question

Using only the periodic table inside the front cover of the text, write the expected ground-state electron configurations for a. the third element in Group $5\mathrm{A}$. b. element number 116 . c. an element with three unpaired $5d$ electrons. d. the halogen with electrons in the $6p$ atomic orbitals.

Short answer

a. The third element in Group 5A is arsenic (As) with electron configuration: $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^3$. b. The electron configuration for element number 116 (Livermorium, Lv) is: $$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^{10}6p^{6}7s^{2}5f^{14}6d^{10}7p^4$$ c. The element with three unpaired 5d electrons is tantalum (Ta) with electron configuration: $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^3$. d. The halogen with electrons in the 6p atomic orbitals is Astatine (At) with electron configuration: $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^{10}6p^5$.

Step-by-step solution

Locate the Element in Group 5A

First, locate Group 5A in the Periodic Table, which includes the elements nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). The third element in this group is arsenic (As) with an atomic number 33.

Determine the electron configuration

To write the electron configuration for arsenic (As), follow the diagonal rule in the Periodic Table (1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, etc.) until you reach atomic number 33. The electron configuration will be: $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^3$ #b. Element number 116#

Locate the Element with atomic number 116

Locate element number 116 located in the F-block of the Periodic Table. This element is called Livermorium (Lv).

Determine the electron configuration

To write the electron configuration for Livermorium (Lv), follow the diagonal rule in the Periodic Table until you reach atomic number 116. The electron configuration will be: $$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^{10}6p^{6}7s^{2}5f^{14}6d^{10}7p^4$$ #c. An element with three unpaired 5d electrons#

Identify the Element containing three unpaired 5d electrons

To find the desired element, first, look for the 5d orbitals group in the Periodic Table. The 5d orbitals are occupied by elements with atomic numbers ranging from 72 to 80.

Find the element

Notice that the 5d orbitals can have up to 10 electrons, but the question asks for an element with only three unpaired 5d electrons. This means that this element needs to have 5d^3 electron configuration. Looking at the sequence of the 5d elements, we find that tantalum (Ta) has three unpaired 5d electrons with the electron configuration: $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^3$ #d. The halogen with electrons in the 6p atomic orbitals#

Locate the Halogens

Halogens are located in Group 7A or Group 17 of the Periodic Table. The members of this group are Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), and Astatine (At).

Find the halogen with 6p electrons

To find the desired halogen, look for the one with electrons in the 6p orbitals. The 6p orbitals are present in the sixth period, hence Astatine (At) is the halogen we are looking for.

Determine the electron configuration

To write the electron configuration for Astatine (At), follow the diagonal rule in the Periodic Table until you reach atomic number 85. The electron configuration will be: $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{14}5d^{10}6p^5$