TYPES OF CHEMICAL BONDS
What is electronegativity?
The ability of an atom in a molecule to attract shared electrons to itself
Which of the following arranges the bonds in order of decreasing bond length?
1. C-P > C-N > C=N 2. C=N > C-P > C-N 3. C-N > C-P > C=N 4. C=N > C-N > C-P
C-P > C-N > C=N
What is an ionic bond?
Electrostatic attraction between a cation (positively charged) and anion (negatively charged)
What does the geometry of molecules depend on?
The number of electron domains (bonds and lone pairs) around the central atom
Define the formal charge of an atom in a molecule
The hypothetical charge the atom would have if ibe can redistribute the electrons in the bonds evenly between the atoms.
Which of the following claims about a P-Cl bond is true? The electronegativity of P is 2.5 and Cl is 3.0.
a) The partial positive charge is on the phosphorus b) The dipole arrow points toward the phosphorus c) There is a sea of electrons between phosphorus and chlorine d) The bond between phosphorus and chlorine is nonpolar.
A) The partial positive charge is on the phosphorus.
Which of the following arranges the bonds in order of decreasing bond length?
C=S > C=O > C ≡ O , C=O > C=S > C≡O , C≡O > C=O , C=S , C≡O > C=S, C=O
C=S > C≡O , C≡O
What must a substance have in order to conduct electricity?
Must have charged particles and particles must be free to move.
What is the molecular geometry of molecules with 120° bond angles?
Trigonal planar, angular
How to calculate for formal charge?
Take the number of valence electrons in a neutral atom, subtract the nonbinding electrons, and then subtract the number of bonds connected to that atom in the Lewis structure.
Using the periodic table, and viewing Si, P, S, and Cl on it, which bond is most polar without looking at the electronegative values?
Si-Si, Si-P, Si-S, or Si-Cl?
Si-Cl
In which of the following ionic compounds is the force of attraction between cation and anion the strongest?
RbI, CsI, MgO, SrS
MgO
What is the molecular geometry of molecules with 109.5° bond angles?
Tetrahedral, Trigonal pyramidal, angular
Calculate the formal charge for each atom in the carbon monoxide molecule:
:C≡O:
C -1, O +1
A student claims that F2 is more polar than H2 because fluorine has a higher electronegativity than hydrogen. Do you agree with this claim? Explain why or why not?
Hydrogen electronegativity: 2.1 Flourine electronegativity: 4.0
No because polarity is the difference in electronegativity, not the absolute value of the electronegativity. Fluorine and hydrogen have the same difference in electronegativity (0), so they have the same polarity.
KBr, RbI, MgO, or CaO
RbI
What are the properties of metallic bonds?
Good conductors of electricity
Malleable- bendable
Ductile- pulled in a wire
What is an example of a trigonal bipyramidal molecule?
PCl5, PF5,
Determine the formal charge for each atom in NCl3
N: 0; all three Cl atoms: 0
Which of the following best predicts the type of bond that forms between Cs and Cl?
Ionic
Covalent bonds form between nonmetals, ionic bonds form between metals and nonmetals, and metallic bonds form between metals.The energy required to separate the ions in a NaCl crystal lattice into individual Na+ (g) and Cl- (g) ions is known as the lattice energy of . As shown in the last sentence, the lattice energy of is greater than the lattice energy of NaCl (s) a similar compound, RbCl (s). NaCl lattice energy- 790 RbCl lattice energy- 695
What best explains why the lattice energy of NaCl is greater than the lattice energy of RbCl?
Na+ has a smaller ionic radius than Rb+, so the distance between cation and anion is shorter in NaCl than RbCl
What is a substitutional alloy?
Atoms of coparable radii
One atom substitutes for another atom in the lattice
Brass- copper and zinc
What is the geometric shape of SF4 best described as?
Seesaw
Assign formal charges to each atom in the interhalogen ion ICl4-
I: 7-8 = -1
Cl: 7-7 = 0