객관식
In order to obtain a stable outer shell of electrons, carbon forms four:
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10. Periodic Properties of the Elements
Valence Electrons of Elements
객관식
Which of the following is the correct number of valence electrons in NH3, and which Lewis structure best represents the molecule?
A
NH3 has 8 valence electrons; the Lewis structure shows nitrogen with a double bond to one hydrogen and single bonds to the other two hydrogens.
B
NH3 has 8 valence electrons; the Lewis structure shows nitrogen with three single bonds to hydrogens and one lone pair.
C
NH3 has 5 valence electrons; the Lewis structure shows nitrogen with three single bonds to hydrogens and one lone pair.
D
NH3 has 6 valence electrons; the Lewis structure shows nitrogen with three single bonds to hydrogens and no lone pairs.
검증된 단계별 안내1
Step 1: Determine the total number of valence electrons in NH3 by adding the valence electrons of nitrogen and hydrogen atoms. Nitrogen is in group 15 and has 5 valence electrons, and each hydrogen has 1 valence electron. So, total valence electrons = 5 (N) + 3 × 1 (H) = 8 electrons.
Step 2: Use the total valence electrons to draw the Lewis structure. Place nitrogen as the central atom because it is less electronegative than hydrogen and can form multiple bonds.
Step 3: Connect each hydrogen atom to nitrogen with a single bond. Each single bond represents 2 electrons, so 3 single bonds use 6 electrons.
Step 4: Distribute the remaining electrons as lone pairs on the nitrogen atom. Since 6 electrons are used in bonds, 8 - 6 = 2 electrons remain, which form one lone pair on nitrogen.
Step 5: Verify the Lewis structure by checking that nitrogen has an octet (8 electrons total: 6 bonding + 2 lone pair) and each hydrogen has 2 electrons (a full shell for hydrogen). This confirms the correct Lewis structure is nitrogen with three single bonds to hydrogens and one lone pair.
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