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Multiple Choice
How many valence electrons are present in a molecule of HCN (hydrogen cyanide)?
A
8
B
12
C
14
D
10
Verified step by step guidance
1
Identify the atoms present in the molecule HCN: hydrogen (H), carbon (C), and nitrogen (N).
Determine the number of valence electrons for each atom based on their group in the periodic table: hydrogen has 1 valence electron, carbon has 4 valence electrons, and nitrogen has 5 valence electrons.
Add the valence electrons from each atom to find the total number of valence electrons in the molecule: total valence electrons = valence electrons of H + valence electrons of C + valence electrons of N.
Write the equation for the total valence electrons: $\text{Total valence electrons} = 1 + 4 + 5$.
Sum the values to find the total number of valence electrons present in the HCN molecule.