Answer each question: 1) Draw the Lewis Dot Structure for nitrogen tribromide, NBr
: 2) How many electrons in your structure above are part of lone pairs? 3) Draw the Lewis Dot Structure for CH
CHO. This compound has 2 central atoms: 4) What specific type of covalent bond is there between the C and O in your structure above?
Answer each question: 1) Draw the Lewis Dot Structure for nitrogen tribromide, NBr
: 2) How many electrons in your structure above are part of lone pairs? 3) Draw the Lewis Dot Structure for CH
CHO. This compound has 2 central atoms: 4) What specific type of covalent bond is there between the C and O in your structure above
The Correct Answer and Explanation is:
Here are the correct answers and explanations for each question:
1) Lewis Dot Structure for Nitrogen Tribromide (NBr₃):
The Lewis structure of NBr₃ shows nitrogen (N) as the central atom with three bromine (Br) atoms bonded to it, and each atom following the octet rule.
..
:Br:
|
:Br–N–Br:
|
..
- Nitrogen forms three single bonds with each of the three bromine atoms.
- Each bromine atom has three lone pairs, and nitrogen has one lone pair.
2) How many electrons in your structure above are part of lone pairs?
Each bromine atom has 3 lone pairs (6 electrons), and there are 3 Br atoms, so:
- Br lone pair electrons: 3 × 3 × 2 = 18 electrons
- N lone pair electrons: 1 lone pair = 2 electrons
- Total lone pair electrons = 18 + 2 = 20 electrons
3) Lewis Dot Structure for CH₃CHO (Acetaldehyde):
CH₃CHO contains a methyl group (CH₃) and a carbonyl group (CHO). The structure looks like this:
H H
\ /
C — C == O
/ ..
H :
- The first carbon (CH₃) is bonded to three hydrogens and the second carbon.
- The second carbon (in CHO) is double bonded to oxygen and single bonded to the first carbon and one hydrogen.
- Oxygen has two lone pairs.
4) What specific type of covalent bond is there between the C and O in your structure above?
The C=O bond is a double covalent bond, consisting of:
- One sigma (σ) bond (from the head-on overlap of orbitals)
- One pi (π) bond (from the sideways overlap of p orbitals)
Explanation
Drawing Lewis dot structures helps us understand molecular bonding and electron distribution. In NBr₃, nitrogen is the central atom with five valence electrons, and each bromine has seven. Nitrogen forms three single covalent bonds with bromine atoms, each sharing one pair of electrons. After bonding, each Br retains six electrons as lone pairs (three pairs), while nitrogen has one lone pair remaining. This gives the molecule 20 electrons in lone pairs — 18 from Br atoms and 2 from N.
For CH₃CHO (acetaldehyde), there are two carbon atoms: one in a methyl group (CH₃) and another in an aldehyde group (CHO). The CH₃ carbon forms single bonds with three H atoms and one C. The aldehyde carbon forms a double bond with oxygen (C=O) and a single bond with a hydrogen atom. This double bond consists of one sigma and one pi bond, which makes it a specific type of covalent bond — a double bond — crucial in organic chemistry, especially in aldehydes and ketones.
Understanding the type of bond is key to predicting reactivity. Double bonds are more reactive than single bonds due to the presence of a pi bond, which is weaker and more easily broken in chemical reactions. Also, lone pairs on oxygen can participate in hydrogen bonding or nucleophilic interactions.
These structural and bonding principles are foundational for predicting molecule shape, polarity, reactivity, and interactions in chemistry.
