Structure And Bonding Flashcards
Which of the following contains a dative covalent bond?
A) N2
B) NH3
C) NH2-
D) NH4+
D ✔️
Which of the following observations provides the best evidence for the presence of ionic bonding in an unknown substance?
The substance conducts electricity... A) in the solid state B) in the solid state and aqueous state C) in the solid state and when molten D) when molten but not in the solid state
D ✔️
Metals usually have high melting temps and boiling temps bc they are:
A) strong attractions between the ions
B) strong attractions between the delocalised electrons
C) strong attractions between the ions and the delocalised electrons
D) strong intermolecular forces
C ✔️
Which of the following does not have exactly 10 electrons?
A) an ion of fluorine m, F-
B) a molecule of methane, CH4
C) a molecule of nitrogen, N2
D) an ion of sodium, Na+
C ✔️
Which in the list below shows the compounds in order of increasing boiling temperature?
A) CH4, HCl, HF
B) HF, CH4, HCl
C) HCl, HF, CH4
D) HF, HCl, CH4
A ✔️✔️ bc the molecules decrease in size
Ethanol is soluble in water. Give one reason why.
Ethanol molecules form hydrogen bonds with water molecules ✔️
What are the properties of graphite?
- electrical conductivity
- hardness
- melting point
- good conductor
- soft
- very high melting point ✔️
Describe the bonding and structure of graphite.
Explain in terms of its properties.
5 marks
- Graphite is arranged in sheets of carbon✔️which have weak IM forces making it soft ✔️
- delocalised electrons carry a charge throughout the structure ✔️
- it has a very high melting point bc the carbons are arranged in sheets ✔️ and have very strong covalent bonds ✔️
What is a covalent bond?
Where e- are shared between atoms ✔️
Draw a “dot and cross” diagram to show the bonding in NH3. Show outer electrons only.
Explain, using your “dot and cross” diagram why ammonia has this shape and has a bond angle of 107 degrees.
This but with shells drawn.
H • x
x x
N
• x
H x • H
Shape: pyramidal
Explanation: 3 bond pairs and 1 lone pair ✔️
NH4Cl is an ionic compound containing NH4+ and Cl- ions.
- Write the electron configuration of a Cl- ion
- Draw a dot and cross diagram for the molecule.
- State the shape and bond angle.
- 1s2 2s2 2p6 3s2 3p6
- — —
| H x x H | + add shells
| x • | around atoms
| N |
| • • |
| H x x H |
— — - Tetrahedral
- 109.5
✔️
Explain what is meant by the term metallic bonding.
The electrostatic attraction between positive and negative metal ions. ✔️
Sodium reacts with Oxygen to form sodium oxide, Na2O, which is an ionic compound.
a) write the equation for the reaction of sodium with oxygen to form sodium oxide.
b) state what is meant by the term ionic bond.
a) 4Na + O2 —> 2Na2O
b) the attraction between oppositely charged ions.✔️
Compare and explain the electrical conductivities of sodium and sodium oxide in the solid and liquid states.
- Na conducts electricity as a liquid state as the IM forces have been overcome so the delocalised e- can carry a charge.✔️
- Na conducts electricity as a solid also bc there is a negative and positive ions throughout the molecule.✔️
- NaO dosent carry a charge while solid bc it’s an ionic bond meaning there are no delocalised e- and the ions are in a fixed position in the lattice. ✔️
What is a dative covalent bond?
When both e- in the bond are supplied by one atom. ✔️
State and explain two anomalous properties of ice caused by hydrogen.
- Ice is less dense than water due to H bonds
2. It is a high melting point bc H bonds are strong.✔️
How many e- can these hold and what are their shape:
a) d-orbitals
b) s-orbitals
c) f-orbitals
d) p-orbitals
a) 10e- and is a dumbbell
b) 2e- and is cloud sphere
c) 14e- and is a dumbbell
d) 6e- and is a dumbbell ✔️
What’s the order of sub shells that fill, up to 4p?
1s -> 4p, what’s in between
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p.✔️
Explain the solubility of ionic compounds.
•dissolve in polar solvents (eg water). Polar water molecules break down the lattice and surround each ion in a solution. ✔️
What are the general properties of ionic compounds?
3 points
- High melting and boiling points
- tend to dissolve in polar solvents
- conduct electricity only in a liquid or aqueous state.✔️
Describe what happens to the 2 separate orbitals when they covalently bond.
The orbitals overlap. ✔️
What are the bond angles for:
- Tetrahedral
- Pyramidal
- Non linear
- Linear
- Trigonal planar
- Octahedral
- 109.5
- 107
- 104.5
- 180
- 120
- 90 ✔️✔️
How many atoms are involved with these shapes:
- Tetrahedral
- Pyramidal
- Non linear
- Trigonal planar
- Linear
- Octahedral
- 6
- 4
- 3
- 4
- 3
- 7 ✔️
What is a polar bond?
When an e- pair is shared unequally between 2 bonded atoms. ✔️
What are induced dipole dipole interactions?
London forces - weak IM forces that exist between all molecules, they act between induced dipoles in different molecules.✔️
Explain induced dip dip interactions.
- It’s instantaneous
- it induces a dipole in a neighbouring molecule
- this continues like dominos ✔️
What are permanent dipole dipole interactions?
They act between permanent dipoles in different polar molecules. (H bonding is a form of this) ✔️
