chemical bonding

	chemical bonding.....aims

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distinguish among ionic, molecular, and metallic substances, given their properties
demonstrate bonding concepts using Lewis dot structures representing valence electrons: transferred (ionic bonding); shared (covalent bonding); in a stable octet
determine the noble gas configuration an atom will achieve when bonding
distinguish between nonpolar covalent bonds (two of the same nonmetals) and polar covalent bonds

fill-in the blanks

Words: arbitrary, broken, conductivity, configuration, covalent, decreases, degree, differentiated, electron-dot, electronegativity, intermolecular forces, ionic, molecular polarity, noble, nonmetals, polar, polyatomic, radius, released, symmetrical, transferred

Compounds can be _____________ by their chemical and physical properties. Two major categories of compounds are _____ and molecular (covalent) compounds. Chemical bonds are formed when valence electrons are: ___________ from one atom to another (ionic), shared between atoms (covalent), mobile within a metal (metallic). In a multiple _________ bond, more than one pair of electrons is shared between two atoms. _________ __________can be determined by the shape of the molecule and the distribution of charge. ____________ (nonpolar) molecules include CO₂, CH₄, and diatomic elements. Asymmetrical (______) molecules include HCl, NH₃, and H₂O. When an atom gains one or more electrons, it becomes a negative ion and its _______ increases. When an atom loses one or more electrons, it becomes a positive ion and its radius __________. When a bond is ________, energy is absorbed. When a bond is formed, energy is _________. Atoms attain a stable valence electron ____________ by bonding with other atoms. _______ gases have stable valence configurations and tend not to bond. Physical properties of substances can be explained in terms of chemical bonds and _____________ ________. These properties include ___________, malleability, solubility, hardness, melting point, and boiling point. _________ - ____ diagrams (Lewis structures) can represent the valence electron arrangement in elements, compounds, and ions. _____________ indicates how strongly an atom of an element attracts electrons in a chemical bond. Electronegativity values are assigned according to _________ scales. The electronegativity difference between two bonded atoms is used to assess the ________ of polarity in the bond. Metals tend to react with _________ to form ionic compounds. Nonmetals tend to react with other nonmetals to form _________ (covalent) compounds. Ionic compounds containing ___________ ions have both ionic and covalent bonding.

real-world connections

saturated vs. unsaturated compounds-health connections
photosynthesis
DNA bonding
free radicals

quiz 1

Question #1
Why is hydrogen gas found in nature as a diatomic molecule rather than a monatomic molecule?
[A] Because the potential energy of H2 is greater than 2 atoms of H.
[B] Because the potential energy of H2 is less than 2 atoms of H.
[C] Because the potential energy of H2 is equal to 2 atoms of H.
[D] Because the potential energy of 2 atoms of H is less than H2.

Question #2
What occurs when two oxygen atoms combine to form O2?
[A] A chemical bond is broken, and energy is released
[B] A chemical bond is formed, and energy is absorbed
[C] A chemical bond is broken, and energy is absorbed
[D] A chemical bond is formed, and energy is released

Question #3
Noble gases have unstable valence configurations and tend not to bond.
True
False

Question #4
Atoms attain a stable valence electron configuration of the noble gases by bonding with other atoms.
True
False

Question #5
Which of the following elements has the highest electronegativity?
[A] Cl
[B] Na
[C] S
[D] Mg

Question #6
When iodine gains one electron it
[A] becomes a positive ion with a smaller radius
[B] becomes a negative ion with a larger radius
[C] becomes a positive ion with a larger radius
[D] becomes a negative ion with a smaller radius

Question #7
How many dots would the electron dot-diagram of N+2 have?
[A] 7
[B] 5
[C] 3
[D] 9

Question #8
An atom's electronegativity determines
[A] its charge
[B] its size of atomic radius
[C] its strength of attraction for electrons in chemical bonds
[D] its type of chemical bond

Question #9
How many dots are to be around He in its Lewis structure?
[A] 1
[B] 6
[C] 8
[D] 2

Question #10
Which of the following species has the smallest radius?
[A] C
[B] C+2
[C] C+4
[D] C-4

quiz 2

Question #1
Compounds can be differentiated only by their physical properties
True
False

Question #2
Which of the following compounds does not belong to the major categories of compounds?
[A] NaCl
[B] Na
[C] NO
[D] CO

Question #3
What is ionization energy?
[A] The energy required to add an electron.
[B] The energy required to remove an electron.
[C] The energy required to add an ion.
[D] The energy required to remove an ion.

Question #4
Metals tend to react with nonmetals to form covalent compound.
True
False

Question #5
Ionic bonds are formed when
[A] valence electrons are shared between bonded atoms
[B] valence electrons are transferred from one atom to another
[C] all the electrons are shared between bonded atoms
[D] all the electrons are transferred from one atom to another

Question #6
Ionic compounds cannot contain both ionic and covalent bonding.
True
False

Question #7
Which compound contains ionic bonds?
[A] NO
[B] CaO
[C] HCl
[D] CO

Question #8
Which compound contains a covalent bond?
[A] HCl
[B] NaCl
[C] KF
[D] BeO

Question #9
Which compound contains both ionic and covalent bonding?
[A] MgCl2
[B] CO2
[C] KNO3
[D] KI

Question #10
In ionic bonds, nonmetals are most likely to
[A] gain electrons
[B] lose electrons
[C] share electrons
[D] cancel electrons

quiz 3

Question #1
When valence electrons are transferred, a covalent bond is formed.
True
False

Question #2
Which is not an identity of the bond formed between 2 hydrogen atoms?
[A] non polar bond
[B] sharring of electrons
[C] single covalent bond
[D] double covalent bond

Question #3
HCl is formed...
[A] when 1 pair of valence electrons is shared, one from the hydrogen atom and one from the chlorine atom.
[B] when 1 pair of valence electrons is shared, none from the hydrogen atom and two from the chlorine atom.
[C] when hydrogen atom give off one valence electron to chlorine atom.
[D] when chlorine atom give off one valence electron to hydrogen atom.

Question #4
Which statement is not true about Cl2 molecule?
[A] 2 valence electrons are shared.
[B] one valence electron from each chlorine atoms are shared.
[C] both chlorine atoms are stable with 8 valence electrons.
[D] one valence electron from each chlorine atoms are transferred.

Question #5
Nonmetals tend to react with other nonmetals to form molecular (covalent) compounds.
True
False

Question #6
In a multiple covalent bond,
[A] only one pair of electrons is shared.
[B] more than one pair of electrons is shared between two atoms.
[C] more than one pair of electrons is shared between four atoms.
[D] more than two pair of electrons is shared between two atoms.

Question #7
How many valence electrons are shared in a double bond?
[A] 2
[B] 6
[C] 4
[D] 8

Question #8
A triple bond is formed when
[A] 1 pair of electrons is shared.
[B] 2 pairs of electrons are shared.
[C] 3 pairs of electrons are shared.
[D] 4 pairs of electrons are shared.

Question #9
What is used to assess the degree of polarity in the bond?
[A] the sum of electronegativity of the two bonded atoms
[B] electronegativity difference of the two bonded atoms
[C] the sum of ionization energy of the two bonded atoms
[D] atomic radius difference of the two bonded atoms

Question #10
Which bond has the highest degree of polarity?
[A] HF
[B] NO
[C] H2
[D] N2

quiz 4

Question #1
Molecular polarity can be determined by the
[A] number of protons
[B] number of electrons
[C] distribution of charge
[D] distribution of neutrons

Question #2
The distribution of charge is determined by the use of
[A] electrons
[B] electronegativity
[C] electropositivity
[D] valence shells

Question #3
Symmetrical molecules are
[A] polar
[B] nonpolar
[C] none of the above

Question #4
In CH4, in which direction are the valence electrons being pulled?
Hint: (draw the Lewis structure of CH4)
[A] closer to the H's
[B] closer to the C
[C] in between the H and C
[D] none of the above

Question #5
The distribution of charge is unequal in an asymmetrical molecule.
True
False

Question #6
Which of the following is a nonpolar molecule?
[A] HCl
[B] NH3
[C] CH4
[D] H2O

Question #7
Hydrogen bonding is an example of a
[A] weak intermolecular force
[B] strong intermolecular force
[C] weak covalent force
[D] strong ionic force

Question #8
Which molecule is nonpolar?
[A] CO2
[B] H2O
[C] NH3
[D] HF

Question #9
Which of the following molecules is polar?
[A] CO2
[B] H2
[C] H2S
[D] SO2

Question #10
H2 is an asymmetrical molecule
True
False

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quiz 5

Question #1
How can the physical properties of substances be explained?
[A] In terms of chemical bonds only
[B] In terms of intermolecular forces only
[C] In terms of chemical bonds and intermolecular forces
[D] In terms of ionic bonding only

Question #2
In general, what do the physical properties of substances include?
[A] conductivity, malleability, solubility and hardness only
[B] conductivity, malleability, solubility, hardness, melting and boiling point only
[C] conductivity, solubility, hardness, melting and boiling point only
[D] solubility, hardness, melting and boiling point only

Question #3
What do ionic solids have between particles?
[A] very strong ionic bonds
[B] very weak ionic bonds
[C] relatively weak ionic bonds
[D] relatively strong ionic bonds

Question #4
What substances have intermolecular forces?
[A] metals
[B] ionic compounds
[C] molecules
[D] electrons

Question #5
Metallic bonds are formed when valence electrons are mobile.
True
False

Question #6
Which is a property of most nonmetallic solids?
[A] high electrical conductivity
[B] malleability
[C] brittleness
[D] high thermal conductivity

Question #7
Which statement describes a chemical property of iron?
[A] Iron conducts electricity and heat
[B] Iron can be drawn into a wire
[C] Iron can be flattened into sheets
[D] Iron combines with oxygen to form rust

Question #8
Which characteristic is a property of molecular substances?
[A] low boiling point
[B] high melting point
[C] good heat conductivity
[D] good electrical conductivity

Question #9
Which substance conducts electricity when melted but not when solid?
[A] a molecular compound
[B] an ionic compound
[C] a metal
[D] a nonmetal

Question #10
Which characteristic is a property of metallic substances?
[A] low boiling point
[B] no conductivity because there are no free moving electrons/ions
[C] not malleable because particles cannot slide pass one another
[D] relatively low solubility

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