CEM 141 FINAL EXAM QUESTIONS
AND ANSWERS 2026
Why are alpha particles deflected by the nucleus? - ANSWERSBecause both the alpha
particles and the nucleus are positively charged and so the alpha particle is repelled.
Is this statement (Dalton's Theory) true or false and why?
"All atoms of an element are identical and have the same mass and properties." -
ANSWERSFalse.
Atoms of the same element can have different numbers of neutrons.
What is the evidence that electrons are subatomic particles? - ANSWERSThe nature of
the electron is independent of the material from which it emerges.
Example of a theory (explains) - ANSWERSThe properties of matter can be
EXPLAINED by understanding that matter is composed of atoms that interact and move
in various predictable ways.
Why is the boiling point of iodine higher than that of bromine? - ANSWERSBecause
iodine has a larger more polarizable electron cloud. The electrostatic attraction between
the iodine molecules requires more energy to overcome.
When bromine melts, what is happening? - ANSWERSAttractive forces between
molecules are overcome.
When oxygen freezes, what is happening with the forces and energy changes during
this process? - ANSWERSNew LDFs are formed. Energy is released to the
surroundings. Energy is transferred via collisions.
Where would two atoms of He be most stable on a PE curve? - ANSWERSThe PE well,
where the attractive and repulsive forces are equal and the system is most stable.
For a pencil sitting on a desk, what forces are acting upon the pencil? - ANSWERSBoth
gravitational and electrostatic.
If the PE increases as two particles approach, what are they most likely? -
ANSWERSTwo protons (positively charged/same charge).
How do atoms know that temperature is increasing? - ANSWERSThermal energy is
transferred upon collision with other atoms.
What two atoms would have the greatest gravitational forces? Two 10g separated by 10
meters. Or, one 100g and one 1g separated by 5 meters?
AND ANSWERS 2026
Why are alpha particles deflected by the nucleus? - ANSWERSBecause both the alpha
particles and the nucleus are positively charged and so the alpha particle is repelled.
Is this statement (Dalton's Theory) true or false and why?
"All atoms of an element are identical and have the same mass and properties." -
ANSWERSFalse.
Atoms of the same element can have different numbers of neutrons.
What is the evidence that electrons are subatomic particles? - ANSWERSThe nature of
the electron is independent of the material from which it emerges.
Example of a theory (explains) - ANSWERSThe properties of matter can be
EXPLAINED by understanding that matter is composed of atoms that interact and move
in various predictable ways.
Why is the boiling point of iodine higher than that of bromine? - ANSWERSBecause
iodine has a larger more polarizable electron cloud. The electrostatic attraction between
the iodine molecules requires more energy to overcome.
When bromine melts, what is happening? - ANSWERSAttractive forces between
molecules are overcome.
When oxygen freezes, what is happening with the forces and energy changes during
this process? - ANSWERSNew LDFs are formed. Energy is released to the
surroundings. Energy is transferred via collisions.
Where would two atoms of He be most stable on a PE curve? - ANSWERSThe PE well,
where the attractive and repulsive forces are equal and the system is most stable.
For a pencil sitting on a desk, what forces are acting upon the pencil? - ANSWERSBoth
gravitational and electrostatic.
If the PE increases as two particles approach, what are they most likely? -
ANSWERSTwo protons (positively charged/same charge).
How do atoms know that temperature is increasing? - ANSWERSThermal energy is
transferred upon collision with other atoms.
What two atoms would have the greatest gravitational forces? Two 10g separated by 10
meters. Or, one 100g and one 1g separated by 5 meters?
