CHEMISTRY MIDTERM REVIEW
2026 EXAM 220 QUESTIONS
AND EXPERT VERIFIED
ANSWERS GRADED A+
Dalton incorporated the law of conservation of mass into his atomic
theory by asserting that - ANSWER= atoms are indivisible
In oxides of nitrogen, such as N₂O, NO, NO₂, and N₂O₃, atoms combine
in small whole-number ratios. This evidence supports the law of -
ANSWER= multiple proportions
According to the law of conservation of mass, when sodium, hydrogen,
and oxygen react to form a compound, the mass of the compound is
_______ the sum of the masses of the individual elements - ANSWER=
equal to
The principles of the atomic theory recognized today were conceived by
- ANSWER= Dalton
,According to Dalton's atomic theory, atoms - ANSWER= of each
element are identical in size, mass, and other properties
True or false: atoms of the same element may have different masses? -
ANSWER= True
Experiments with cathode rays led to the discovery of the - ANSWER=
electron
Whose series of experiments identified the nucleus of the atom? -
ANSWER= Rutherford
Because most particles fired at metal foil passed straight through,
Rutherford concluded that - ANSWER= atoms were mostly empty
space
A positively charged particle with mass 1.673 x 10⁻²⁴ g is a -
ANSWER= proton
A nuclear particle that has about the same mass as a proton but with no
electrical charge is called a - ANSWER= neutron
True or false: The nucleus of an atom contains nearly all of the atom's
volume - ANSWER= false
, True or false: The nucleus of an atom is positively charged -
ANSWER= true
True or false: The nucleus of an atom contains nearly all of the atom's
mass - ANSWER= true
True or false: The nucleus of an atom is very dense - ANSWER= true
Which part of an atom has a mass approximately equal to 1/2000 of the
mass of a common hydrogen atom? - ANSWER= electron
Protons within the nucleus are attracted to each other by - ANSWER=
the nuclear force
An atom is electrically neutral because - ANSWER= the numbers of
protons and electrons are equal
Most of the volume of an atom is occupied by the - ANSWER=
electrons
The smallest unit of an element that can exist either alone or in
combination with other such particles of the same or different elements
is the - ANSWER= atom
The radius of an atom extends to the outer edge of the - ANSWER=
region occupied by the electrons
2026 EXAM 220 QUESTIONS
AND EXPERT VERIFIED
ANSWERS GRADED A+
Dalton incorporated the law of conservation of mass into his atomic
theory by asserting that - ANSWER= atoms are indivisible
In oxides of nitrogen, such as N₂O, NO, NO₂, and N₂O₃, atoms combine
in small whole-number ratios. This evidence supports the law of -
ANSWER= multiple proportions
According to the law of conservation of mass, when sodium, hydrogen,
and oxygen react to form a compound, the mass of the compound is
_______ the sum of the masses of the individual elements - ANSWER=
equal to
The principles of the atomic theory recognized today were conceived by
- ANSWER= Dalton
,According to Dalton's atomic theory, atoms - ANSWER= of each
element are identical in size, mass, and other properties
True or false: atoms of the same element may have different masses? -
ANSWER= True
Experiments with cathode rays led to the discovery of the - ANSWER=
electron
Whose series of experiments identified the nucleus of the atom? -
ANSWER= Rutherford
Because most particles fired at metal foil passed straight through,
Rutherford concluded that - ANSWER= atoms were mostly empty
space
A positively charged particle with mass 1.673 x 10⁻²⁴ g is a -
ANSWER= proton
A nuclear particle that has about the same mass as a proton but with no
electrical charge is called a - ANSWER= neutron
True or false: The nucleus of an atom contains nearly all of the atom's
volume - ANSWER= false
, True or false: The nucleus of an atom is positively charged -
ANSWER= true
True or false: The nucleus of an atom contains nearly all of the atom's
mass - ANSWER= true
True or false: The nucleus of an atom is very dense - ANSWER= true
Which part of an atom has a mass approximately equal to 1/2000 of the
mass of a common hydrogen atom? - ANSWER= electron
Protons within the nucleus are attracted to each other by - ANSWER=
the nuclear force
An atom is electrically neutral because - ANSWER= the numbers of
protons and electrons are equal
Most of the volume of an atom is occupied by the - ANSWER=
electrons
The smallest unit of an element that can exist either alone or in
combination with other such particles of the same or different elements
is the - ANSWER= atom
The radius of an atom extends to the outer edge of the - ANSWER=
region occupied by the electrons
