Chapter 1: Chemistry: The Science of Change $6.36
● Chemistry is the field dedicated to examining matter and the transformations it
experiences.
● Matter is defined as anything that occupies space and possesses mass.
● All scientists must adhere to the scientific method, a specific set of guidelines for
experimentation, to ensure their results are accepted and contribute to the collective
knowledge base of their field, even though their individual approaches may vary.
● Scientists often use a law to summarize observed patterns or trends. A law is a brief
verbal or mathematical statement that describes a dependable relationship between
different phenomena.
● Once scientists have summarized their findings into a law, they can then develop a
hypothesis, which is a tentative explanation for their observations.
● A theory serves as a comprehensive concept that integrates a set of experimental
observations and the fundamental laws derived from them, providing an explanation for
both.
● The International System of Units (SI, from the French Système Internationale
d’Unités) is the name given to the revised metric system.
● All other units of measurement are derived from the seven SI base units. For example,
the SI unit for volume is derived by cubing (raising to the power of 3) the SI unit for
length.
● The quantity of matter present in an object or sample is measured by its mass.
● The atomic mass unit (amu) is, as its name indicates, the unit used to express the
masses of atoms and other similarly sized objects.
● The angstrom (Å), a non-SI unit of length, is a common example, alongside the atomic
mass unit, of a unit preferred for a specific application even though it is not an SI unit.
One angstrom is equal to 1 ✕ 10⁻¹⁰ meters.
● The Celsius scale, named for Swedish physicist Ander Celsius (1701-1744), was initially
established based on the freezing point (0°C) and the boiling point (100°C) of pure water
at sea level.
● The SI base unit for temperature is the kelvin, as illustrated in image 1.
Image 1 The Seven SI Base Units
Base Quantity Unit Name Unit Symbol
Time second s
Length meter m
Mass kilogram kg
Electric current ampere A
Thermodynamic temperature kelvin K
, Amount of substance mole mol
Luminous intensity candela cd
Image 1
● Density is defined as the ratio of mass to volume.
● A reported number's meaningful digits are known as significant figures.
● The degree to which a measurement approximates the actual value is known as
accuracy.
● Precision refers to the degree of agreement among a set of identical measurements (or
replicate measurements), indicating how closely they cluster together (image 2).
Image 2
● A conversion factor is a ratio, presented as a fraction, that expresses the same
quantity in both the numerator and the denominator but uses different units or forms of
expression.
● Dimensional analysis, also known as the factor-label method, is the technique of using
conversion factors to solve problems.
● A substance is a specific type of matter, distinguished by its unique chemical
composition and characteristic properties. These observable properties can include its
color, its state (solid, liquid, or gas), and whether or not it dissolves in water (solubility).
● A mixture is formed when two or more substances are combined, with each component
maintaining its separate, unique identity.
● A homogenous mixture results when sodium chloride is dissolved in water because the
mixture's composition is uniform throughout.
● A heterogeneous mixture is the term for a mixture, like sand and iron filings, in which
the components remain distinct and discernible because the composition is not uniform.
,● A physical process is defined as one where the identity of any substance remains
unchanged.
● A substance's properties are described as either:
○ Quantitative: Measured and expressed numerically.
○ Qualitative: Described without explicit measurement or the use of numbers.
● A property that can be observed and measured without altering the substance's identity
is called a physical property.
● Melting is a physical change, meaning the state of matter is altered without changing
the substance's chemical identity.
● Iron's ability to rust when exposed to water and air is classified as a chemical property.
This is because observing the rusting process necessitates a chemical change or
chemical process to take place.
● An extensive property's measured value is dependent on the quantity of matter
present.
● An intensive property is independent of the quantity of matter present.
Chapter 2: Atoms and the Periodic Table
● An atom is defined as the smallest unit of matter that maintains the characteristic
properties of that matter.
● An element is a substance that is located further from an atom and cannot be broken
down into two or more simpler substances through any method.
● During the late 1800s, scientific investigations often centered on radiation, which is the
emission and transmission of energy in the form of waves.
● When a high-voltage source is connected to the metal plates inside a partially evacuated
glass tube (a cathode ray tube), the negatively charged plate, called the cathode,
releases radiation known as cathode rays.
● In a series of experiments, J. J. Thomson used a variable electric field to measure the
deflection of cathode rays. This allowed him to calculate the charge-to-mass ratio of the
small, negatively charged particles, which are now called electrons.
● Wilhelm Röntgen observed that when cathode rays were directed at glass or metal, they
produced another form of radiation, which he termed X rays.
● Radioactivity is the term for the spontaneous emission of radiation that occurs in
uranium.
● Alpha (ɑ) rays are composed of positively charged ɑ particles. Because of this positive
charge, they are observed to be deflected away from a positively charged plate.
● Beta (β) particles, also known as β rays, are fundamentally electrons. Due to their
negative charge, they are observed to be deflected away from the negatively charged
plate.
● The third type of radioactive emission, following alpha and beta rays, is composed of
high-energy gamma (ɣ) rays.
● Ernest Rutherford proposed that the atom's positive charges are concentrated in an
extremely dense central core, which he named the nucleus.
● Protons are the positively charged particles found in the nucleus.
● Later experiments revealed a third type of subatomic particle, named neutrons by
James Chadwick. This was discovered when a thin sheet of beryllium was bombarded
, with alpha particles, emitting very high-energy radiation. This radiation was similar to
gamma rays, yet it consisted of particles that were not deflected by electric or magnetic
fields, indicating they were electrically neutral. Furthermore, neutrons were found to have
a mass slightly greater than that of protons.
● The atomic number (Z), which is the number of protons found in the nucleus of an
atom, uniquely identifies each element.
● The mass number (A), also known as the number of nucleons, represents the total
count of protons and neutrons within an atom's nucleus.
● Most elements have two or more isotopes—atoms with the same atomic number (Z) but
different mass numbers (A). This means the concept that all atoms of a given element
are identical is no longer strictly accurate.
● The atomic mass is defined as the mass of a single atom, expressed in atomic mass
units.
● The periodic table (Image 3) is composed of 118 elements.
Image 3
● Horizontal rows in the periodic table are known as periods. The elements are arranged
within these rows by increasing atomic number.
● Metals are typically good conductors of heat and electricity, in contrast to nonmetals,
which are generally poor conductors.
● An element is classified as a metalloid if its properties fall in between those of typical
metals and nonmetals.
● A group is the term for a vertical column of elements found in the periodic table.
● The elements in Group 1 of the periodic table—Lithium (Li), Sodium (Na), Potassium (K),
Rubidium (Rb), Cesium (Cs), and Francium (Fr)—are known as the alkali metals.
Similarly, the Group 2 elements—Beryllium (Be), Magnesium (Mg), Calcium (Ca),
● Chemistry is the field dedicated to examining matter and the transformations it
experiences.
● Matter is defined as anything that occupies space and possesses mass.
● All scientists must adhere to the scientific method, a specific set of guidelines for
experimentation, to ensure their results are accepted and contribute to the collective
knowledge base of their field, even though their individual approaches may vary.
● Scientists often use a law to summarize observed patterns or trends. A law is a brief
verbal or mathematical statement that describes a dependable relationship between
different phenomena.
● Once scientists have summarized their findings into a law, they can then develop a
hypothesis, which is a tentative explanation for their observations.
● A theory serves as a comprehensive concept that integrates a set of experimental
observations and the fundamental laws derived from them, providing an explanation for
both.
● The International System of Units (SI, from the French Système Internationale
d’Unités) is the name given to the revised metric system.
● All other units of measurement are derived from the seven SI base units. For example,
the SI unit for volume is derived by cubing (raising to the power of 3) the SI unit for
length.
● The quantity of matter present in an object or sample is measured by its mass.
● The atomic mass unit (amu) is, as its name indicates, the unit used to express the
masses of atoms and other similarly sized objects.
● The angstrom (Å), a non-SI unit of length, is a common example, alongside the atomic
mass unit, of a unit preferred for a specific application even though it is not an SI unit.
One angstrom is equal to 1 ✕ 10⁻¹⁰ meters.
● The Celsius scale, named for Swedish physicist Ander Celsius (1701-1744), was initially
established based on the freezing point (0°C) and the boiling point (100°C) of pure water
at sea level.
● The SI base unit for temperature is the kelvin, as illustrated in image 1.
Image 1 The Seven SI Base Units
Base Quantity Unit Name Unit Symbol
Time second s
Length meter m
Mass kilogram kg
Electric current ampere A
Thermodynamic temperature kelvin K
, Amount of substance mole mol
Luminous intensity candela cd
Image 1
● Density is defined as the ratio of mass to volume.
● A reported number's meaningful digits are known as significant figures.
● The degree to which a measurement approximates the actual value is known as
accuracy.
● Precision refers to the degree of agreement among a set of identical measurements (or
replicate measurements), indicating how closely they cluster together (image 2).
Image 2
● A conversion factor is a ratio, presented as a fraction, that expresses the same
quantity in both the numerator and the denominator but uses different units or forms of
expression.
● Dimensional analysis, also known as the factor-label method, is the technique of using
conversion factors to solve problems.
● A substance is a specific type of matter, distinguished by its unique chemical
composition and characteristic properties. These observable properties can include its
color, its state (solid, liquid, or gas), and whether or not it dissolves in water (solubility).
● A mixture is formed when two or more substances are combined, with each component
maintaining its separate, unique identity.
● A homogenous mixture results when sodium chloride is dissolved in water because the
mixture's composition is uniform throughout.
● A heterogeneous mixture is the term for a mixture, like sand and iron filings, in which
the components remain distinct and discernible because the composition is not uniform.
,● A physical process is defined as one where the identity of any substance remains
unchanged.
● A substance's properties are described as either:
○ Quantitative: Measured and expressed numerically.
○ Qualitative: Described without explicit measurement or the use of numbers.
● A property that can be observed and measured without altering the substance's identity
is called a physical property.
● Melting is a physical change, meaning the state of matter is altered without changing
the substance's chemical identity.
● Iron's ability to rust when exposed to water and air is classified as a chemical property.
This is because observing the rusting process necessitates a chemical change or
chemical process to take place.
● An extensive property's measured value is dependent on the quantity of matter
present.
● An intensive property is independent of the quantity of matter present.
Chapter 2: Atoms and the Periodic Table
● An atom is defined as the smallest unit of matter that maintains the characteristic
properties of that matter.
● An element is a substance that is located further from an atom and cannot be broken
down into two or more simpler substances through any method.
● During the late 1800s, scientific investigations often centered on radiation, which is the
emission and transmission of energy in the form of waves.
● When a high-voltage source is connected to the metal plates inside a partially evacuated
glass tube (a cathode ray tube), the negatively charged plate, called the cathode,
releases radiation known as cathode rays.
● In a series of experiments, J. J. Thomson used a variable electric field to measure the
deflection of cathode rays. This allowed him to calculate the charge-to-mass ratio of the
small, negatively charged particles, which are now called electrons.
● Wilhelm Röntgen observed that when cathode rays were directed at glass or metal, they
produced another form of radiation, which he termed X rays.
● Radioactivity is the term for the spontaneous emission of radiation that occurs in
uranium.
● Alpha (ɑ) rays are composed of positively charged ɑ particles. Because of this positive
charge, they are observed to be deflected away from a positively charged plate.
● Beta (β) particles, also known as β rays, are fundamentally electrons. Due to their
negative charge, they are observed to be deflected away from the negatively charged
plate.
● The third type of radioactive emission, following alpha and beta rays, is composed of
high-energy gamma (ɣ) rays.
● Ernest Rutherford proposed that the atom's positive charges are concentrated in an
extremely dense central core, which he named the nucleus.
● Protons are the positively charged particles found in the nucleus.
● Later experiments revealed a third type of subatomic particle, named neutrons by
James Chadwick. This was discovered when a thin sheet of beryllium was bombarded
, with alpha particles, emitting very high-energy radiation. This radiation was similar to
gamma rays, yet it consisted of particles that were not deflected by electric or magnetic
fields, indicating they were electrically neutral. Furthermore, neutrons were found to have
a mass slightly greater than that of protons.
● The atomic number (Z), which is the number of protons found in the nucleus of an
atom, uniquely identifies each element.
● The mass number (A), also known as the number of nucleons, represents the total
count of protons and neutrons within an atom's nucleus.
● Most elements have two or more isotopes—atoms with the same atomic number (Z) but
different mass numbers (A). This means the concept that all atoms of a given element
are identical is no longer strictly accurate.
● The atomic mass is defined as the mass of a single atom, expressed in atomic mass
units.
● The periodic table (Image 3) is composed of 118 elements.
Image 3
● Horizontal rows in the periodic table are known as periods. The elements are arranged
within these rows by increasing atomic number.
● Metals are typically good conductors of heat and electricity, in contrast to nonmetals,
which are generally poor conductors.
● An element is classified as a metalloid if its properties fall in between those of typical
metals and nonmetals.
● A group is the term for a vertical column of elements found in the periodic table.
● The elements in Group 1 of the periodic table—Lithium (Li), Sodium (Na), Potassium (K),
Rubidium (Rb), Cesium (Cs), and Francium (Fr)—are known as the alkali metals.
Similarly, the Group 2 elements—Beryllium (Be), Magnesium (Mg), Calcium (Ca),
