acs molecular structure
When the carbon-carbon bonds in ethane (C₂H₆),ethene (C₂H₄), and benzene (C₆H₆) are arranged in order of increasing length (shortest bonds first), what is the correct order? (A) C₂H₆ < C₂H₄< C₆H₆ (B) C₂H₄ < C₂H₆ < C₆H₆ (C) C₆H₆ < C₂H₄ < C₂H₆ (D) C₂H₄ < C₆H₆ < C₂H₆
C₂H₄ < C₆H₆ < C₂H₆
What is the shape of the XeF₄ molecule?
HAS A LONE PAIR thats why its a square planar
BOILING POINT OF H2O CAN BE EXPLAINED BY
HYDROGEN BONDING
Which concept describes the formation of four equivalent, single, covalent bonds by carbon in its compounds that resemble methane, CH₄? (A) hydrogen bonding (B) hybridization (C) sigma bonding (D) coordinate covalent bonding
hybridization
A compound consisting of an element having 1. a low ionization energy 2. a second element having a high electron affinity is likely to have
ionic bonds
a simple method showing experimentally that a solid substance may be ionic is to show that it
conducts current when dissolved in water
Which compound would be expected to have the largest dipole moment? (A) C0₂ (linear) (B) S0₂(bent) (C) BF₃ (trigonal planar) (D) CF₄ (tetrahedral)
for dipole it has to be bent
Molecules of which compounds violate the octet N0₂ CH₂C1₂ XeF₄ NC1₃ 1 2 3 4 (A) 1and 2 (B) l and 3 (C) 2 and 3 (D) 2 and 4
l and 3 need to have lone apirs to violate it
Resonance structures describe molecules that have
multiple electron-dot formulas.
metallic bonds
result when atoms free one or more valence electrons to the metal lattice.
coordinate covalent bonds
similar but one of the two atoms furnishes both electrons
Which type of hybrid orbital is used in C0₂? (A) sp (B) sp² (C) sp³ (D) dsp³
sp because its straight linear line
The fact that Pt(NH₃)₂Cl₂ exists in two different isomeric forms offers evidence that the geometry is (A) octahedral. (B) square planar. (C) tetrahedral. (D) trigonal planar.
square planar.
Consider the given Lewis structure for BrF₅• What is the predicted shape for the molecule as a whole? (A) square pyramidal (B) trigonal bipyramidal (C) trigonal pyramidal (D) octahedral
square pyramidal looks like a clock and HAS A LONE PAIR
Consider the Lewis structure for CH3Cl. What is the best description of the molecular shape? Check your book for picture (A) bent (B) square (C) square pyramidal (D) tetrahedral
tetrahedral
The molecule of the type ML₄ consists of four single bonds and NO lone pairs. What structure is it expected to assume?
tetrahedral
The structure of the CO₃²⁻ ion can be described in the Lewis formulation by these structures. This means that
the CO₃²⁻ ion exists in only one form: an average of the three principal structures shown
Which of these is a nonpolar molecule?
the linear one C2F4
The shape that most closely describes the NF₃ molecule is (A) octahedral. (B) trigonal planar. (C) trigonal pyramidal. (D) tetrahedral.
trigonal planar.
covalent bonds
when atoms each contribute an electron to a shared pair
ionic bond
when atoms exchange electrons
The 0-Si-O bond angles in Si0₂ (quartz) are closest to (A) 180° (B) 120° (C) 110° (D) 100°
110 because its a double double SiO2
.. .. The molecule :O=C=N-H has been detected in gas clouds between stars. The predicted C-N-H bond angle is about (A) 90° (B) 109° (C) 120° (D) 180°
120°
a double = how many sigma and pi
1s 1p
3 bond
1s 2p
NH₃ (pyramidal geometry) reacts with BF₃ (planar geometry) to form the addition compound, H₃NBF₃• What is the geometry around the nitrogen and boron centers in the addition compound?
Both centers are tetrahedral
The compound CF₃CHCIF is being considered as a replacement for CBrF₃ as a fire-extinguishing agent because CBrF₃ has been shown to deplete stratospheric ozone. What are the most probable products if a molecule of CF₃CHClF is bombarded with high-energy photons?
CF₃CHF + C one with the least ennergy
Which species has both covalent and ionic bonds? (A) NH₃BF₃ (B) H₃O⁺ (C) NaKS (D) Mg(CN)₂
Mg(CN)₂
Which element is most likely to form a triple bond? (A) Pb (B) F (C) N (D) S
N
For which molecule can the bonding be described in terms of sp³ hybrid orbitals of the central atom? (A) SF₆ (B) BF₃ (C) PC1₅ (D) NH₃
NH3
What set of species is arranged in order of increasing 0-N-O bond angle? (A) No₂⁻, N0₂, NO₂⁺ (B) N0₂, No₂⁻,NO₂⁺ (C) NO₂⁺, N0₂, N02₂⁻ (D) N0₂, NO₂⁺, N0₂⁻
No₂⁻, N0₂, NO₂⁺ from negative to more positive
Which molecule has exactly 2 unshared (lone) pairs of electrons on the central atom? (A) BF₃ (B) OF₂ (C) NF₃ (D) XeF₂
OF₂
Knowing that F is more electronegative than either B or P, what conclusion can be drawn from the fact that BF₃ has no dipole moment, but PF₃ does? (A) BF₃ is not spherically symmetrical, but PF₃ is. (B) The BF₃ molecule must be trigonal planar. (C) The BF₃ molecule must be linear. (D) The atomic radius of P is larger than the atomic radius of B.
The BF₃ molecule must be trigonal planar.
The fact that BC1₃ is a planar molecule while NCl₃ is pyramidal can be explained several different ways. Which statement is the best rationalization? (A)Nitrogen is more electronegative than boron. (B)The nitrogen atom in NC1₃ has a lone pair of electrons, whereas the boron atom in BC1₃ does not. (C) The nitrogen atom is smaller than the boron atom. (D) The boron atom in BC1₃ is sp³ hybridized, while the nitrogen atom in NC1₃ is sp² hybridized
The nitrogen atom in NC1₃ has a lone pair of electrons, whereas the boron atom in BC1₃ does not.
Which hasthe largest bond angle? (A) angle 0-S-O in So₄²⁻ (B) angle C1-C-C1 in HCC1₃ (C) angle F-Be-F in BeF₂ (D) angle H-O-H in H₂O
angle F-Be-F in BeF₂ has to be linear for 180
According to the VSEPR model, the geometric structure of H₂0 is
bent at an angle of 104.5° because of the greater repulsion of two lone pairs relative to that of the two bonding pairs.