Start by drawing the Lewis structure of .  has  valence electrons.

Since the nitrogen has  oxygen atoms bonded to it and a lone pair, the steric number must be . From that, we know that it must have sp² hybridization.

Look at each of the carbon atoms in the chain. Each carbon atom has  other atoms bonded to it. This means that the steric number of each carbon is . Thus, the only type of hybridization found in this molecule is sp².

Start by counting the number of atoms the nitrogen is bonded to. It has  bonded atoms. The nitrogen also has a lone pair. This means the steric number of the nitrogen is . Thus, it must have  hybridization.

Notice that there are  groups bonded to the sulfur. The groups are the double bond to the oxygen, the lone pair, and the bonds to the two separate carbons.

Since there are  groups on the sulfur, it must have  hybridization.

Start by drawing the Lewis structure.

Notice that selenium has  groups around it: 4 bromines and 1 lone pair.

Molecules with  electron groups will exhibit  hybridization.

For this question, we're asked to identify which kind of hydridization, if any, a carbonyl carbon of a ketone group will have.

First, let's recall that a ketone group is a functional group in which a carbon atom contains a double bond to an oxygen atom. In addition, the carbon also has a single bond to each of two other atoms, neither of which are hydrogen.

Let's also recall that a double bond consists of one sigma bond and one pi bond. Each of the two single bonds that carbon has to the other atoms will also be sigma bonds, because these are both single bonds. Thus, in total, this carbon atom will have three sigma bonds and one pi bond.

In order to have a pi bond, there must be p orbital overlap. Thus, one out of the three p orbitals from the carbon will be used towards contributing to the pi bond with the oxygen. Consequently, we have one s orbital and two p orbitals left over. These three orbitals can hybridize to become three  orbitals. Each of these  orbitals will take place in the three sigma bonds that the carbon atom has.

Count the number of groups that the sulfur has attached to it. It is attached to , two oxygen atoms, an done carbon. Since there are four groups attached to the sulfur, it must have  hybridization.

Start by recalling that nitrous acid is .

Next, draw its Lewis Structure:

Notice that the nitrogen is bonded to two oxygen atoms. The nitrogen atom also has a lone pair. Since there are  groups attached to the nitrogen, it must have  hybridization.

In ethylene, the two central Carbon atoms are bonded together with a double covalent bond. In order to form a double bond, Carbon always takes on  hybridization. The double bond consists of a sigma bond caused by the overlapping of a pair of  hybridized orbitals and a pi bond caused by the overlapping of neighboring unhybridized  orbitals. Further,   hybridization always results in hybrid orbitals that are oriented in a trigonal planar manner, with a separation angle of 120° for maximum electron separation between the three sigma-bonding  orbitals. Thus, all other answers are incorrect.

In HCN, Carbon is bonded to Nitrogen with a triple covalent bond consisting of one sigma bond and two pi bonds. The sigma bond is formed by overlapping  hybridized orbitals, with the two remaining unhybridized  orbitals overlapping to form the two pi bonds.