CHEM 103 PRACTICE EXAMINATION 2026
QUESTIONS WITH ANSWERS GRADED A+
◍ Understand how bond polarity arises.
Answer: if electron distribution is unequal -> polar bonds(this due to large
enough ∆X)bond polarity: relative equity/inequity in electron sharing
◍ Understand how electronegativity plays a role in electron sharing and
ultimately bond type.
Answer: smaller difference in electronegativity-> more equal sharingatom
w/ higher x gets more of electron pairif sufficiently unequal (∆x is large
enough) -> ionic bond
◍ Understand how to carry units through calculations.
Answer: - can help direct to correct answerensure all units are used in
calculationidentify proper units for answerensure al units cancel to obtain
proper units in solution
◍ Be familiar with electron filling sequence (watch those d-orbitals!).
Answer: 1s , 2s, 2p, 3s, 3p4s, 3d,3p, 4s, 3d,4p, 5s, 4d,5p, 6s, 4f, 5d
◍ Mole.
Answer: Relates number of atoms/molecules to grams
◍ To find the mass of 1 mole....
Answer: Replace units of amu with Grams
◍ how is avagadros number used.
Answer: NAa collective unit (like a dozen)to scale the number of
atoms/particles to more reasonable numbers
◍ Know what bond order means.
Answer: number of electron pairs shared btw two atoms
,◍ Understand the discovery cycle.
Answer: observation -> hypothesis -> experimentoutcomes: what (natural
law)why (logical model)
◍ frequency.
Answer: the number of waves that pass a given point per secondunits:
(1/sec)determines light energy--symbol mu
◍ Chalcogens.
Answer: Group 16
◍ Be familiar with significant figures (see handout!).
Answer: is to use scientific notation-- all nonzero are significant--all captive
zeros are significatn--leading zeros not significant--trailing zeros significant
if followed by decimal pointSome numbers are exact and have no limit on
sig figs
◍ Understand Effective Nuclear Charge (Zeff).
Answer: Z_effelectrostatic charge experienced by outer electronincreases up
and to the right
◍ Ionic compound formula represents.
Answer: ratio of cations to anions, not a distinct molecular formula.
◍ Average mass equation.
Answer: sum of (fractional abundance x isotopic mass)
◍ Wave length.
Answer: distance between waves
◍ Covalent Bond.
Answer: Generally between two nonmetals or nonmetals and semimetals.
Electrons are being shared
◍ Empiracal formula.
Answer: indicates the types of atoms present and the simplest whole-number
ratio of the number of atoms (or ions) in the compound.
◍ Lower wavelength =.
, Answer: higher energy
◍ Understand the relationship between theory, prediction, and experiment.
Answer: the understand cycletheorieslead topredictionlead to experiments
modifytheories
◍ Weighted average of isotope equation is....
Answer: (fraction isotope 1 x mass isotope 1) x (fraction isotope 2 x mass
isotope 2)
◍ Understand what happens if you gain or lose protons.
Answer: different element
◍ ionic bond.
Answer: Generally between a metal and a nonmetal. Electrons are
transferred and electrostatic force (ionic bond) occurs between (+) and (-).
◍ Understand trends in atomic size and the reasoning behind the trends.
Answer: increases down and to the lefthigher n -> increased r_avgincreased
Z_eff -> decreased r_avg
◍ Avg. Atomic mass and Molar mass are ...
Answer: numerically equivalent
◍ Understand size trends in ions.
Answer: cationic charge - ↓sizeanionic charge - ↑ size
◍ Understand molecular vs. empirical formula..
Answer: Molecular Formula: Atoms are listed, along with the number of
each atom (not neccesarily reduced --think of glucose)Empirical
Formula:simplest whole number ratio---simplified molecular formula
◍ Proton.
Answer: A subatomic particle that has a positive charge and that is found in
the nucleus of an atom
◍ Be familiar with how nuclei were discovered.
Answer: rutherfordgold foil experimentalpha beam pointed at gold
foil99.995% went straight through0.005% deflected by nucleiimplied there
QUESTIONS WITH ANSWERS GRADED A+
◍ Understand how bond polarity arises.
Answer: if electron distribution is unequal -> polar bonds(this due to large
enough ∆X)bond polarity: relative equity/inequity in electron sharing
◍ Understand how electronegativity plays a role in electron sharing and
ultimately bond type.
Answer: smaller difference in electronegativity-> more equal sharingatom
w/ higher x gets more of electron pairif sufficiently unequal (∆x is large
enough) -> ionic bond
◍ Understand how to carry units through calculations.
Answer: - can help direct to correct answerensure all units are used in
calculationidentify proper units for answerensure al units cancel to obtain
proper units in solution
◍ Be familiar with electron filling sequence (watch those d-orbitals!).
Answer: 1s , 2s, 2p, 3s, 3p4s, 3d,3p, 4s, 3d,4p, 5s, 4d,5p, 6s, 4f, 5d
◍ Mole.
Answer: Relates number of atoms/molecules to grams
◍ To find the mass of 1 mole....
Answer: Replace units of amu with Grams
◍ how is avagadros number used.
Answer: NAa collective unit (like a dozen)to scale the number of
atoms/particles to more reasonable numbers
◍ Know what bond order means.
Answer: number of electron pairs shared btw two atoms
,◍ Understand the discovery cycle.
Answer: observation -> hypothesis -> experimentoutcomes: what (natural
law)why (logical model)
◍ frequency.
Answer: the number of waves that pass a given point per secondunits:
(1/sec)determines light energy--symbol mu
◍ Chalcogens.
Answer: Group 16
◍ Be familiar with significant figures (see handout!).
Answer: is to use scientific notation-- all nonzero are significant--all captive
zeros are significatn--leading zeros not significant--trailing zeros significant
if followed by decimal pointSome numbers are exact and have no limit on
sig figs
◍ Understand Effective Nuclear Charge (Zeff).
Answer: Z_effelectrostatic charge experienced by outer electronincreases up
and to the right
◍ Ionic compound formula represents.
Answer: ratio of cations to anions, not a distinct molecular formula.
◍ Average mass equation.
Answer: sum of (fractional abundance x isotopic mass)
◍ Wave length.
Answer: distance between waves
◍ Covalent Bond.
Answer: Generally between two nonmetals or nonmetals and semimetals.
Electrons are being shared
◍ Empiracal formula.
Answer: indicates the types of atoms present and the simplest whole-number
ratio of the number of atoms (or ions) in the compound.
◍ Lower wavelength =.
, Answer: higher energy
◍ Understand the relationship between theory, prediction, and experiment.
Answer: the understand cycletheorieslead topredictionlead to experiments
modifytheories
◍ Weighted average of isotope equation is....
Answer: (fraction isotope 1 x mass isotope 1) x (fraction isotope 2 x mass
isotope 2)
◍ Understand what happens if you gain or lose protons.
Answer: different element
◍ ionic bond.
Answer: Generally between a metal and a nonmetal. Electrons are
transferred and electrostatic force (ionic bond) occurs between (+) and (-).
◍ Understand trends in atomic size and the reasoning behind the trends.
Answer: increases down and to the lefthigher n -> increased r_avgincreased
Z_eff -> decreased r_avg
◍ Avg. Atomic mass and Molar mass are ...
Answer: numerically equivalent
◍ Understand size trends in ions.
Answer: cationic charge - ↓sizeanionic charge - ↑ size
◍ Understand molecular vs. empirical formula..
Answer: Molecular Formula: Atoms are listed, along with the number of
each atom (not neccesarily reduced --think of glucose)Empirical
Formula:simplest whole number ratio---simplified molecular formula
◍ Proton.
Answer: A subatomic particle that has a positive charge and that is found in
the nucleus of an atom
◍ Be familiar with how nuclei were discovered.
Answer: rutherfordgold foil experimentalpha beam pointed at gold
foil99.995% went straight through0.005% deflected by nucleiimplied there
