How many valence electrons does HCN have? 10 8 5 12

## Step 1<br />The number of valence electrons in a molecule is the sum of the valence electrons of each atom in the molecule. <br /><br />## Step 2<br />Hydrogen (H) has 1 valence electron, Carbon (C) has 4, and Nitrogen (N) has 5. <br /><br />## Step 3<br />Adding these together, we get \(1 + 4 + 5 = 10\). <br /><br />## Step 4<br />However, in the molecule HCN, the Nitrogen atom forms a triple bond with the Carbon atom, which means it shares 6 electrons with the Carbon atom. <br /><br />## Step 5<br />This leaves 4 electrons on the Nitrogen atom, which are not involved in bonding. <br /><br />## Step 6<br />Therefore, the total number of valence electrons in the HCN molecule is \(10 - 6 = 4\). <br /><br />## Step 7<br />Adding the 1 electron from the Hydrogen atom, we get \(4 + 1 = 5\).