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Multiple Choice
In the Lewis dot structure of AsCl_3, how many lone pairs of electrons are present on the As atom?
A
2
B
0
C
3
D
1
Verified step by step guidance
1
Determine the total number of valence electrons for the central atom, arsenic (As). Arsenic is in group 15, so it has 5 valence electrons.
Recognize that each chlorine (Cl) atom contributes 1 electron for bonding, and there are 3 chlorine atoms, so 3 bonding pairs are formed between As and Cl atoms.
Draw the Lewis structure by placing As in the center and connecting it to three Cl atoms with single bonds, using 3 pairs of electrons for bonding.
Calculate the remaining valence electrons on As after bonding: subtract the 3 bonding pairs (6 electrons) from the total valence electrons of As (5 electrons). Since bonding electrons are shared, consider that As contributes one electron per bond, so the leftover electrons on As are 2 (one lone pair).
Conclude that the arsenic atom has 1 lone pair of electrons in the Lewis structure of AsCl_3.