Question 1
What is a chemical bond?
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A force of attraction between atoms
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A reaction that always releases light
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A mixture of two elements
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A change of state from liquid to gas
Question 2
Ionic bonding forms when?
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Electrons are transferred from one atom to another
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Electrons are shared equally in pairs
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Neutrons move between nuclei
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Atoms overlap to form mixtures
Question 3
Covalent bonding involves?
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Sharing pairs of electrons
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Losing all outer-shell electrons
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Gaining protons in the nucleus
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Separating atoms into ions only
Question 4
Metallic bonding is the attraction between?
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Positive metal ions and delocalized electrons
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Negative ions and shared electron pairs
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Neutral atoms and neutrons
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Molecules and hydrogen ions
Question 5
Why do ionic compounds usually have high melting points?
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Strong electrostatic attractions act throughout a giant lattice
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They contain only weak intermolecular forces
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Their atoms are not bonded at all
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They always have very small molecules
Question 6
Why do simple molecular substances often have low melting and boiling points?
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Forces between molecules are relatively weak
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Covalent bonds inside molecules are weak
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Their nuclei are unstable
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They always contain metals
Question 7
Why can graphite conduct electricity?
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It has delocalized electrons that can move
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It has ionic bonds between carbon atoms
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It contains free protons
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It is made from metal atoms
Question 8
Why is diamond very hard?
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Each carbon atom is strongly covalently bonded in a giant 3D structure
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It contains layers that slide over each other
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It is made of ionic molecules
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It has weak forces between small molecules
Question 9
Which substance has ionic bonding?
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Sodium chloride (NaCl)
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Oxygen (O2)
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Methane (CH4)
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Carbon dioxide (CO2)
Question 10
Which substance is a simple molecular covalent substance?
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Carbon dioxide (CO2)
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Sodium chloride (NaCl)
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Magnesium oxide (MgO)
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Silicon dioxide (SiO2)
Question 11
When does solid sodium chloride conduct electricity?
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When molten or dissolved in water, not when solid
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Only when solid
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Only as a gas
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Always in every state equally
Question 12
Why are metals malleable?
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Layers of metal ions can slide while metallic bonding is maintained
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Metals are made of separate molecules with weak forces
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Metals contain no electrons
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Metal atoms are not arranged in a structure
Question 13
What is a polymer?
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A very large molecule made from repeating smaller units
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A pure metal with delocalized electrons
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A compound made from ionic crystals only
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A gas with a low boiling point
Question 14
Which statement about water (H2O) is correct?
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It is a covalent compound with shared electrons
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It is an ionic compound with transferred electrons only
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It is a metallic structure of hydrogen and oxygen ions
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It is a mixture, not a compound
Question 15
Why are ionic solids brittle?
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Shifting layers can bring like charges together so they strongly repel
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Ions can move freely in the solid
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They contain no fixed structure
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They are made from neutral molecules only
Question 16
Which formula represents methane?
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CH4
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C2H6
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CO2
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H2O
Question 17
Which substance has a giant covalent structure?
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Silicon dioxide (SiO2)
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Oxygen (O2)
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Hydrogen chloride (HCl)
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Water (H2O)
Question 18
Why does copper conduct electricity as a solid?
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Its delocalized electrons are free to move through the lattice
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Copper ions are free to flow as a liquid
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It contains covalent molecules with weak forces
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Electrons are fixed in place on each atom
Question 19
In covalent bonding, atoms share electrons mainly for what reason?
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Fill their outer electron shells and become more stable
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Increase their number of protons
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Become positively charged ions
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Remove all electrons from the atom
Question 20
Which pair of element types most often forms an ionic compound?
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A metal and a non-metal
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Two non-metals
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Two noble gases
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Two transition metals only
Question 21
How is an ionic bond formed?
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By electrostatic attraction between oppositely charged ions after electron transfer
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By sharing pairs of electrons between atoms
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By attraction between neutral molecules only
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By proton transfer between non-metals
Question 22
What is the formula of magnesium oxide formed from Mg2+ and O2-?
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MgO
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Mg2O
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MgO2
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Mg2O3
Question 23
Why do ionic compounds usually have high melting points?
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Strong electrostatic attractions act in all directions in a giant ionic lattice
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They contain weak intermolecular forces only
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Ionic bonds break easily at low temperatures
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Ions are not bonded in the solid state
Question 24
Why does solid sodium chloride not conduct electricity?
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Its ions are fixed in place and cannot move to carry charge
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It has no charged particles
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Its electrons are free to move
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Sodium chloride has covalent bonding only
Question 25
When does sodium chloride conduct electricity?
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When molten or dissolved in water
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Only when solid
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Only when cooled below room temperature
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Only as a gas
Question 26
What is a covalent bond?
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A shared pair of electrons between atoms
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A transferred pair of protons
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An attraction between positive metal ions only
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A force between ions in solution only
Question 27
Why do simple molecular substances like CO2 often have low boiling points?
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Weak intermolecular forces are overcome on boiling
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Covalent bonds inside molecules are weak
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Their molecules are ionic lattices
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They contain no electrons
Question 28
What type of structure does diamond have?
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A giant covalent structure where each carbon bonds to four others
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Layers of carbon with weak forces between layers
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A giant ionic lattice of carbon ions
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Small molecules with weak forces
Question 29
Why can graphite conduct electricity?
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It has delocalized electrons that can move through the structure
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It contains mobile ions in the solid
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Each carbon atom has no outer electrons
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It is made of metallic bonds only
Question 30
Why is graphite soft and slippery?
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Its layers can slide because weak forces act between layers
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Its covalent bonds are weak within each layer
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It has no bonds between carbon atoms
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It is a liquid at room temperature
Question 31
Which statement about graphene is correct?
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It is a single layer of carbon atoms and is a good electrical conductor
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It is a gas made of C60 molecules
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It is an ionic compound of carbon and oxygen
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It is an insulator because it has no electrons
Question 32
What best describes metallic bonding?
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Attraction between positive metal ions and delocalized electrons
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Attraction between neutral metal atoms only
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Sharing electron pairs between metal and non-metal atoms
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Attraction between negative ions and protons
Question 33
Why are metals good conductors of electricity?
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Delocalized electrons are free to move through the metal
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Metal ions can leave the lattice in the solid state
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Metals contain free protons that move
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Metals are made of simple molecules
Question 34
Why are alloys usually harder than pure metals?
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Different-sized atoms distort layers and make sliding harder
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Alloys contain no metallic bonds
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Alloys always have weaker bonding than pure metals
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Alloy atoms are perfectly aligned so layers slide easily
Question 35
Which substance has a giant covalent structure?
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Silicon dioxide (SiO2)
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Methane (CH4)
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Oxygen (O2)
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Hydrogen chloride (HCl)
Question 36
What size range defines nanoparticles?
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About \(1\text{ to }100\,\mathrm{nm}\)
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About \(1\text{ to }100\,\mathrm{mm}\)
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About \(1\text{ to }100\,\mathrm{\mu m}\)
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About \(1000\text{ to }10{,}000\,\mathrm{nm}\)
Question 37
Why are nanoparticles often more reactive than larger particles of the same substance?
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They have a much larger surface area to volume ratio
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Their atoms have more protons
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They always have ionic bonding
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They contain no electrons
Question 38
What is one concern about widespread nanoparticle use?
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Possible health or environmental effects are not always fully known
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Nanoparticles cannot enter any living cells
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Nanoparticles always behave exactly like bulk materials
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All nanoparticles are non-reactive in the body
Question 39
Which statement about polymers is correct?
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Polymers are long-chain molecules made from many repeating units
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Polymers are always giant ionic lattices
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All polymers are metals
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Polymers are mixtures with no chemical bonds
Question 40
Why does iodine (I2) have a much lower boiling point than sodium iodide (NaI)?
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I2 is simple molecular with weak intermolecular forces, while NaI is ionic with strong electrostatic attractions
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I2 has stronger ionic bonds than NaI
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NaI is made of simple molecules with weak forces
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Both have identical bonding and boiling points