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Multiple Choice
In the Lewis structure for BeCl_2, how many lone pairs of electrons are present on the central beryllium atom?
A
0
B
1
C
4
D
2
Verified step by step guidance
1
Identify the total number of valence electrons for the central atom, beryllium (Be). Beryllium is in group 2 of the periodic table, so it has 2 valence electrons.
Determine the number of valence electrons contributed by the surrounding atoms. Each chlorine (Cl) atom is in group 17 and contributes 7 valence electrons, but for the Lewis structure, focus on bonding pairs between Be and Cl.
Draw the Lewis structure by placing beryllium in the center and connecting it to two chlorine atoms with single bonds. Each bond represents a pair of shared electrons (2 electrons per bond).
Count the electrons around the central beryllium atom. Since Be forms two single bonds, it shares 4 electrons in total, which satisfies its valence shell in this case (an exception to the octet rule).
Determine the number of lone pairs on the central atom by subtracting the bonding electrons from the total valence electrons of Be. Since all valence electrons are involved in bonding, the number of lone pairs on Be is zero.