what does the Lewis Dot Structure of Sr(CN)2 look like?
I would write it as an ionic compound with Sr^2+ and 2CN^-
The dot structure for CN^- is
:C:::N:-
To determine the Lewis dot structure of Sr(CN)2, we need to follow a step-by-step method:
Step 1: Calculate the total number of valence electrons for the compound.
- Sr (strontium) is in Group 2A and has 2 valence electrons.
- C (carbon) is in Group 4A and has 4 valence electrons.
- N (nitrogen) is in Group 5A and has 5 valence electrons.
- Multiply the number of valence electrons for each element by the corresponding number of atoms and sum them up.
2 * (2 valence electrons for Sr) + 1 * (4 valence electrons for C) + 2 * (5 valence electrons for N) = 2 + 4 + 10 = 16 valence electrons
Step 2: Determine the central atom.
- In Sr(CN)2, strontium (Sr) is the central atom as it can form more bonds than carbon or nitrogen.
Step 3: Connect the atoms using single bonds.
- Strontium (Sr) forms a bond with each carbon (C) atom and each nitrogen (N) atom.
Step 4: Subtract the number of electrons used in the bonds from the total valence electrons calculated in Step 1.
16 valence electrons - 2 electrons used in each Sr-C bond - 2 electrons used in each Sr-N bond = 8 valence electrons remaining.
Step 5: Distribute the remaining electrons to fulfill the octet rule for each atom.
- Place the remaining electrons, in pairs, around the outer atoms (carbon and nitrogen) until they have an octet (except for hydrogen, which can have only two electrons).
- Unused electrons are placed on the central atom (strontium) to provide it with an octet.
The Lewis dot structure for Sr(CN)2 is as follows:
:
..:..
.CG:':CN.
..`. ..
:S-N:
:
In this structure, the central strontium atom (Sr) is connected to two carbon atoms (C) and two nitrogen atoms (N) through single bonds (represented by lines). The outer atoms (carbon, nitrogen) have a full octet of electrons (8 electrons), and the central strontium atom has an expanded octet with 10 electrons.
To determine the Lewis dot structure of Sr(CN)2, we must consider the number of valence electrons of each element.
- Strontium (Sr) is in group 2, so it has 2 valence electrons.
- Carbon (C) is in group 14, so it has 4 valence electrons.
- Nitrogen (N) is in group 15, so it also has 5 valence electrons.
We multiply the number of valence electrons of each element by the number of atoms present:
- Sr: 1 atom × 2 valence electrons = 2 valence electrons
- C: 1 atom × 4 valence electrons = 4 valence electrons
- N: 2 atoms × 5 valence electrons = 10 valence electrons
In total, we have 2 + 4 + 10 = 16 valence electrons.
Let's construct the Lewis dot structure step-by-step:
1. Identify the central atom: In this case, it is Sr since it is the least electronegative.
2. Place the remaining atoms around the central atom: Place the two CN groups around Sr.
3. Connect the central atom to each surrounding atom using a single bond: Connect Sr with each CN group using a single bond (represented by a straight line).
4. Distribute the remaining electrons: Distribute the remaining electrons around each atom starting with the surrounding atoms. Each carbon atom has a lone pair of electrons, and nitrogen atoms have three lone pairs each. Place the remaining electrons on the Sr atom.
5. Check if all atoms obey the octet rule: Count the number of electrons around each atom. Carbon and nitrogen atoms each have eight electrons (including the lone pairs), while strontium has two electrons. Therefore, we need to share the remaining two valence electrons of Sr as a lone pair.
The final Lewis dot structure of Sr(CN)2 is as follows:
..
:Sr::
..
:CN:
..
:CN:
..