General Chemistry Principles and Atomic Theory Flashcards

Comprehensive practice flashcards covering fundamental chemistry concepts, matter and energy, physical and chemical changes, atomic models, subatomic particles, quantum numbers, electron configurations, and periodic trends.

What is the definition of chemistry and why is it referred to as the central science?

Chemistry is the science that studies matter, its properties, the changes it undergoes, and the energy involved in those changes. It is called the central science because it connects other fields such as biology, medicine, pharmacy, physics, and environmental science.

What are the five major branches of chemistry and their primary focus areas?

1. Organic Chemistry: Hydrocarbons and their derivatives. 2. Inorganic Chemistry: Elements, metals, minerals, salts, and inorganic compounds. 3. Analytical Chemistry: Identifies substances and determines their quantities in samples. 4. Biochemistry: Chemical substances and processes in living organisms. 5. Physical Chemistry: Behavior of matter and energy changes involved in processes.

How are mass, weight, and volume defined and distinguished?

Mass is a measure of the amount of matter in an object and remains constant. Weight is the force exerted on an object by gravity and changes when gravitational force changes. Volume is the amount of three-dimensional space occupied by a substance or object.

What is the distinction between kinetic energy and potential energy?

Kinetic energy is the energy of motion possessed by moving particles, flowing liquids, and gases. Potential energy is stored energy that may be released when a physical or chemical change occurs.

How do exothermic and endothermic processes differ in terms of heat transfer?

An exothermic process releases heat from the system to the surroundings, whereas an endothermic process absorbs heat from the surroundings into the system.

How do solids, liquids, and gases differ in particle arrangement, shape, and volume?

Solids have closely packed particles vibrating in fixed positions, with definite shape and volume. Liquids have particles close together that move past one another, with definite volume but taking the shape of their container. Gases have particles far apart moving freely in all directions, with no definite shape or volume.

What are the six phase change processes that occur between solids, liquids, and gases?

Melting (solid to liquid), Freezing (liquid to solid), Vaporization (liquid to gas), Condensation (gas to liquid), Sublimation (solid to gas), and Deposition (gas to solid).

What is the difference between a physical property and a chemical property?

A physical property can be observed or measured without changing the chemical composition or identity of a substance. A chemical property describes the ability of a substance to react or change into one or more new substances.

How do extensive properties differ from intensive properties?

Extensive properties depend on the amount of matter present (such as mass, volume, length, and total energy). Intensive properties do not depend on the amount of matter present (such as density, color, hardness, melting point, boiling point, and conductivity).

What is the difference between a physical change and a chemical change?

A physical change affects the form, appearance, size, shape, or physical state of matter without changing its chemical composition. A chemical change produces one or more new substances with compositions and properties distinct from the original substance.

What are six possible signs that indicate a chemical change has taken place?

1. Permanent color change 2. Gas formation 3. Formation of a precipitate 4. Heat release or absorption 5. Light production 6. Odor production.

How are pure substances and mixtures classified?

Pure substances have a fixed and definite composition and are classified as elements or compounds. Mixtures consist of two or more physically combined substances in variable proportions and are classified as homogeneous or heterogeneous mixtures.

What are five common physical methods used to separate mixtures?

1. Filtration: Separates an insoluble solid from a liquid. 2. Evaporation: Removes a liquid to leave a dissolved solid. 3. Distillation: Separates based on differences in boiling points. 4. Decantation: Separates a liquid from a settled solid or immiscible liquid. 5. Centrifugation: Uses rapid spinning to separate substances with different densities.

How are pharmaceutical solutions and suspensions categorized as mixtures?

A solution (such as normal saline) is a homogeneous mixture where the drug is completely dissolved. A suspension is a heterogeneous mixture containing solid particles dispersed in a liquid that may settle during storage.

What are the electrical charges, approximate masses, and locations of protons, neutrons, and electrons?

Protons have a charge of $+1$, an approximate mass of $1\,\text{amu}$, and are in the nucleus. Neutrons have a charge of $0$, an approximate mass of $1\,\text{amu}$, and are in the nucleus. Electrons have a charge of $-1$, an approximate mass of nearly $0\,\text{amu}$, and are located outside the nucleus.

How are atomic number ($Z$) and mass number ($A$) defined?

Atomic number ($Z$) is the number of protons in the nucleus of an atom. Mass number ($A$) is the total number of protons and neutrons in the nucleus.

How are cations and anions formed, and how are their total numbers of electrons calculated?

A cation is a positively charged ion formed when an atom loses electrons ($\text{Electrons} = \text{Atomic number} - \text{Positive charge}$). An anion is a negatively charged ion formed when an atom gains electrons ($\text{Electrons} = \text{Atomic number} + \text{Magnitude of negative charge}$).

For a neutral Carbon-13 atom, what are the numbers of protons, neutrons, and electrons?

Carbon-13 has an atomic number of $6$ and a mass number of $13$, so it contains $6$ protons, $7$ neutrons ($13 - 6$), and $6$ electrons.

What are isotopes and how is atomic weight calculated?

Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons. Atomic weight is the weighted average mass of the naturally occurring isotopes of an element, expressed as a decimal.

Who proposed that matter was composed of indivisible particles called atomos around 500 BCE?

Leucippus and Democritus.

What key atomic contributions were made by J. J. Thomson, Robert Millikan, Ernest Rutherford, and James Chadwick?

J. J. Thomson discovered electrons using cathode-ray tubes (Plum-pudding model). Robert Millikan determined electron charge via the oil-drop experiment. Ernest Rutherford discovered the small, dense, positive nucleus via the gold-foil experiment (Nuclear model). James Chadwick discovered neutral particles called neutrons by bombarding beryllium with alpha particles.

How did Niels Bohr describe electron behavior in the Bohr Planetary Model?

Bohr proposed that electrons move around the nucleus in specific circular paths called orbits, where each orbit corresponds to a definite, quantized energy level.

What contributions were made by Louis de Broglie, Werner Heisenberg, and Erwin Schrödinger to quantum mechanics?

Louis de Broglie proposed wave-particle duality. Werner Heisenberg introduced the uncertainty principle, stating that position and momentum cannot be known simultaneously. Erwin Schrödinger developed a wave equation leading to the quantum-mechanical model, defining orbitals as probability regions for finding electrons.

What three principles govern the writing of electron configurations?

1. Aufbau Principle: Electrons fill lower-energy orbitals before higher-energy orbitals. 2. Pauli Exclusion Principle: An orbital can hold a maximum of two electrons with opposite spins. 3. Hund's Rule: Orbitals of equal energy are occupied singly before electron pairing begins.

What do the four quantum numbers ($n$, $l$, $m_l$, $m_s$) represent?

1. Principal Quantum Number ($n$): Main energy level or shell. 2. Angular Momentum Quantum Number ($l$): Subshell and orbital shape. 3. Magnetic Quantum Number ($m_l$): Specific orbital orientation in space. 4. Spin Quantum Number ($m_s$): Spin orientation of an electron ($+\frac{1}{2}$ or $-\frac{1}{2}$).

What are the allowed values of $l$ and the corresponding subshell labels when $n = 3$?

When $n = 3$, allowed values of $l$ are $0$, $1$, or $2$, corresponding to the 3s, 3p, and 3d subshells.

What is Modern Periodic Law, and how are periods and groups defined?

Modern Periodic Law states that properties of elements are periodic functions of their atomic numbers. Horizontal rows are periods (sharing the number of occupied electron shells). Vertical columns are groups or families (sharing valence electron arrangements and chemical properties).

What are the valence electron counts and common ion charges for Alkali Metals, Alkaline Earth Metals, Chalcogens, and Halogens?

Alkali Metals (Group 1): 1 valence electron, form $+1$ ions. Alkaline Earth Metals (Group 2): 2 valence electrons, form $+2$ ions. Chalcogens (Group 16): 6 valence electrons, form $-2$ ions. Halogens (Group 17): 7 valence electrons, form $-1$ ions.

How are the four blocks of the periodic table (s, p, d, f) classified?

Blocks are classified based on the subshell being filled by the highest-energy electrons: s-block (Groups 1, 2, H, He), p-block (Groups 13 to 18 except He), d-block (transition metals in Groups 3 to 12), and f-block (lanthanides and actinides).

How does atomic radius change across a period and down a group?

Atomic radius decreases from left to right across a period due to increasing nuclear charge pulling electrons closer. It increases from top to bottom down a group as additional occupied energy levels increase electron shielding and distance from the nucleus.

What is ionization energy, and why do successive ionization energies increase dramatically after valence electrons are removed?

Ionization energy is the energy required to remove an electron from an isolated gaseous atom ($\text{Atom} + \text{energy} \rightarrow \text{positive ion} + \text{electron}$). Successive ionization energies increase because each electron is removed from an increasingly positive ion, showing a massive spike when an electron must be taken from a stable inner shell.

What is electronegativity, which element is the most electronegative, and how does it trend across the periodic table?

Electronegativity is the relative ability of an atom to attract shared electrons toward itself in a chemical bond. Fluorine is the most electronegative element. Electronegativity increases across a period (due to smaller atomic radius and greater nuclear charge) and decreases down a group (due to larger atomic size and shielding).