Question

question 4
1 pts
an octahedral compound probably has what hybridization of the central atom?
$sp^3d$
$sp^2$
$sp$
$sp^3d^2$
question 5
1 pts
the electronic arrangement is the same as the molecular shape when
the atoms are joined by sigma bonds.
there are no lone pairs of electrons on the central atom.
the molecule is not polar.
there are more shared electrons than nonshared electrons.
question 6
1 pts
after constructing the lewis dot formula for $cf_3^-$, give its electronic arrangement and molecular shape.
trigonal planar, trigonal planar
trigonal bipyramidal, t - shaped
tetrahedral, trigonal pyramidal
tetrahedral, angular

Explanation:

Question 4

Step1: Recall hybridization - shape relation

Hybridization and molecular geometry are related. For octahedral geometry, the central atom needs 6 hybrid orbitals.

Step2: Analyze each option

• $sp^3d$: Gives trigonal bipyramidal geometry (5 orbitals).
• $sp^2$: Gives trigonal planar geometry (3 orbitals).
• $sp$: Gives linear geometry (2 orbitals).
• $sp^3d^2$: Involves 1 $s$, 3 $p$, and 2 $d$ orbitals, totaling 6 orbitals, which matches octahedral geometry.

Question 5

Electronic arrangement considers bonding + lone pairs; molecular shape considers only bonding pairs. When there are no lone pairs on the central atom, bonding pairs determine both, so they match. Sigma bonds, polarity, or shared - nonshared electron ratio don't ensure this match.

Question 6

Step1: Calculate electron groups for $CF_3^-$

Central C atom: valence electrons = 4, 3 F atoms (each contributes 1 electron) and 1 negative charge. Total electron groups: 4 (3 bonding with F, 1 lone pair from the negative charge? Wait, no: $CF_3^-$ has C as central, 3 single bonds to F, and 1 lone pair? Wait, no, let's do Lewis structure. C has 4, 3 F (each 7, but in bonds, so 3 single bonds: 3×1 (from C) + 3×7 (F) + 1 (charge) = 4 + 21+1 = 26. Lewis structure: C is bonded to 3 F, and has 1 lone pair (since 4 + 3×1 (bonds) + 2 (lone pair electrons? Wait, no, formal charge: For C: 4 - (3 + 2) = -1, which matches. So electron arrangement (electron - group geometry) is tetrahedral (4 electron groups: 3 bonding, 1 lone). Molecular shape (molecular geometry) is trigonal pyramidal (3 bonding, 1 lone).

Step2: Match with options

• Trigonal planar (3 groups) doesn't fit.
• Trigonal bipyramidal (5 groups) no.
• Tetrahedral (electron) and trigonal pyramidal (molecular) matches.
• Angular (bent) would be 2 bonding, 2 lone, no.

Answer:

D. $sp^3d^2$