Comprehensive TYT Chemistry Definitive Study Guide

Foundations of Chemical Science and the Legacy of Alchemy

Chemistry as a modern science emerged from the ancient practice of Alchemy, also known as Alŗimi. The primary goals of alchemists were the transmutation of base (worthless) metals into gold and the discovery of the elixir of immortality. Despite its lack of a systematic scientific methodology, alchemy was deeply intertwined with various fields of study and belief systems, including astronomy, astrology, medicine, philosophy, mythology, and religion. During their pursuits, alchemists developed several essential laboratory tools and equipment that are still used in modified forms today, such as the furnace (fırın), alembic (imbik), hand balance (el kantırı), crucible (kroze), spirit level (su terazisi), and the water bath (su banyosu).

Significant practical discoveries were made during the alchemical period, including the development of gunpowder (barut), ceramics (seramik), glass (cam), essence (esans), and ink (m0urekkep). They also discovered chemical substances like mercury (cıva), various alloys (alaőım), and powerful acids, such as hydrochloric acid ($HCl$), historically referred to as "tuz ruhu"; nitric acid ($HNO_3$), known as "kezzap"; and sulfuric acid ($H_2SO_4$), referred to as "zaç yağı."

Modern Chemical Disciplines and Industries

Chemistry is subdivided into numerous specialized disciplines to manage the vast scope of chemical interactions. Biochemistry focuses on chemical processes within living organisms. Analytical Chemistry is concerned with the qualitative and quantitative determination of chemical components. Physical Chemistry (Fizikokimya) examines the physical properties of molecules and the relationships between energy and chemical systems. Inorganic Chemistry (Anorganik kimya) studies non-carbon-based compounds, while Organic Chemistry focuses on carbon-based compounds. Polymer Chemistry investigates the synthesis and properties of large molecular chains, and Industrial Chemistry (End0ustriyel kimya) deals with the manufacturing of chemicals on a commercial scale. These disciplines support major sectors including the pharmaceutical industry (İlaç End0ustrisi), fertilizer production (G0ubre End0ustrisi), petrochemistry, water and air purification (Arıtım), and the textile industry.

The Symbolic Language of Chemistry: Elements and Compounds

Elements are pure substances consisting of a single type of atom that cannot be broken down into simpler substances by physical or chemical means. Every element is defined by the number of protons in its nucleus, known as the atomic number, and is represented by a unique chemical symbol. Currently, there are $118$ known elements, of which $92$ occur naturally, while the others are synthesized artificially in laboratories. Elements are organized in the periodic table and classified as metals, non-metals, semi-metals, or noble gases. They are homogenous and possess specific melting and boiling points. Elements can exist in atomic form (e.g., $He$, $Ne$, $Li$, $Na$), diatomic molecular form (e.g., $N_2$, $Cl_2$, $O_2$), or polyatomic form (e.g., $O_3$, $P_4$, $Se$).

Compounds are pure and homogenous substances formed when at least two different elements chemically combine in a specific mass ratio, losing their individual chemical properties in the process. Compounds are represented by formulas (e.g., $H_2O$) and can only be separated into their constituent elements via chemical methods.

Chemical Safety Symbols and Laboratory Equipment

Safety in the laboratory is communicated through universal warning signs. Flammable substances have low ignition temperatures and catch fire easily upon heating (e.g., alcohol, acetone). Oxidizing (Yakıcı) substances, such as $O_2$, $Cl_2$, $HNO_3$, and $H_2O_2$, must not come into contact with flammable materials. Corrosive (Aőındırıcı) substances like $NaOH$, $H_2SO_4$, and $HF$ can damage metal, glass, and tissue. Irritants (Tahriő Edici), such as $NaClO$ and $C_2H_5OH$, harm the skin, eyes, and respiratory tract. Explosive substances like nitroglycerin must avoid heat, sparks, or impact. Toxic (Zehirli) substances cause poisoning through ingestion, skin contact, or inhalation (e.g., hydrogen sulfide, ethylenamine). Radioactive substances cause permanent damage to living tissues and require protective clothing. Environmentally harmful substances have long-lasting negative effects on air, water, and soil; this symbol is found on all chemical containers.

Key laboratory equipment includes the Beaker (Beherglas) for solution preparation and boiling; the Glass Flask (Cam Balon) for storing solutions; the Burette for titration with graduated scales; the Pipette for transferring precise liquid volumes; the Volumetric Flask (Balonjoje) for preparing solutions of specific concentrations; the Separatory Funnel (Ayırma Hunisi) for separating heterogeneous liquid-liquid mixtures; the Graduated Cylinder (Dereceli Silindir) for volume measurement; the Erlenmeyer flask for storing and filtering; the Mortar (Havan) for grinding solids; and the Crucible (Kroze) for dissolving or ashing substances.

Evolution of Atomic Models

The understanding of the atom has evolved through several key models. Dalton proposed that atoms are indivisible, indestructible solid spheres. Thomson introduced the "plum pudding" model, suggesting the atom is a sphere of approximately $10^{-8}\,cm$ in diameter where positive and negative charges are balanced to maintain neutrality. Rutherford discovered through experiment that the positive charge is concentrated in a tiny central nucleus, with the rest of the atom being mostly empty space where electrons orbit. Bohr refined this by stating electrons move in specific, quantized circular orbits called energy levels or shells. Moving further from the nucleus increases the energy of the orbit. Atoms can absorb energy to move an electron to an "excited state" (Uyarılmıő Hal) and emit energy as they return to their "ground state" (Temel Hal).

Atomic Structure and Classification

Atoms consist of subatomic particles: protons (positively charged), neutrons (neutral), and electrons (negatively charged). The protons and neutrons reside in the nucleus and are collectively referred to as nucleons. The mass number ($A$) is the sum of protons ($Z$) and neutrons ($N$). In a neutral atom, the atomic number equals the number of protons and the number of electrons. For ions, the charge is calculated as: $\text{Ion Charge} + \text{Electron Number} = \text{Proton Number}$. Anions are formed when atoms gain electrons, while cations are formed when they lose electrons.

Atoms are classified based on their composition: Isotopes have the same number of protons but different numbers of neutrons (e.g., $_{15}^{30}X$ and $_{15}^{31}X$). Isotopes of the same element generally share chemical properties unless they are ions. Isotones have different proton numbers but matching neutron numbers. Isobars share the same mass number but have different atomic numbers. Isoelectronic species have the same number of electrons and identical electron configurations but different proton numbers (e.g., $K^+$ and $Ar$ with $18$ electrons each).

The Periodic System and Element Classification

The periodic table consists of $7$ horizontal periods and $18$ vertical groups. Groups are named by letters and numbers ($1A$-$8A$, $1B$-$10B$) or numerically (1–18) according to IUPAC. A-groups are the main group elements, while B-groups are transition elements (metals). Special group names include: $1A$ Alkali Metals, $2A$ Alkaline Earth Metals, $3A$ Earth Metals, $6A$ Chalcogens, $7A$ Halogens, and $8A$ Noble Gases. Electrons fill energy levels sequentially (K: max 2, L: max 8, M: max 18). Atoms seek their most stable ground state configuration. Helium ($He$) is an exception, having $2$ valence electrons but belonging to the $8A$ group.

Elements are broadly classified: Metals are good conductors of heat and electricity, are malleable, and solid at room temperature (except mercury, $Hg$). Non-metals can be solids, liquids, or gases; they are poor conductors (except graphite) and appear dull. Semi-metals ($B$, $Si$, etc.) are solid at room temperature and behave physically like metals but chemically like non-metals. Noble gases are monatomic, stable gases with full outer shells (8 electrons, except $He$ with 2).

Periodic Trends and Properties

Atomic radius (atomic volume) increases down a group due to more energy shells and decreases across a period from left to right as the nuclear charge increases. Ionization Energy ($IE$) is the minimum energy required to remove an electron from a gaseous atom in its ground state. Successive ionization energies always increase ($IE_1 < IE_2 < IE_3 \dots$). Across a period, $IE$ generally increases, though stability differences in groups $2A$/$3A$ and $5A$/$6A$ create an order of $1A < 3A < 2A < 4A < 6A < 5A < 7A < 8A$.

Electron Affinity is the energy change when a gaseous atom gains an electron; it generally increases across a period and decreases down a group. Electronegativity is the power of an atom in a covalent bond to attract shared electrons; Fluorine ($F$) is the most electronegative element, while noble gases are considered to have zero electronegativity. Metallic character increases toward the bottom-left of the table, while non-metallic character increases toward the top-right.

Chemical Species and Their Interactions

Chemical species include atoms (smallest unit of an element), molecules (groups of non-metal atoms), and ions (charged atoms or groups). Interactions are classified as strong (chemical bonds) or weak (physical interactions). A change in energy greater than $40\,kJ/mol$ usually signifies the breaking or forming of strong interactions. Strong interactions include ionic, covalent, and metallic bonds. Weak interactions include Van der Waals forces and Hydrogen bonds.

Ionic bonds involve the transfer of electrons, typically between a metal and a non-metal. Lewis structures represent valence electrons as dots around the symbol. Covalent bonds involve the sharing of electrons between non-metals. Polar covalent bonds occur between different atoms (e.g., $HCl$), while apolar covalent bonds occur between identical atoms (e.g., $H_2$). Molecules are polar if the charge distribution is asymmetric (e.g., $H_2O$) and apolar if symmetric (e.g., $CH_4$).

Naming Compounds and Intermolecular Forces

Ionic compounds are named by the cation followed by the anion (e.g., $Al_4C_3$ is Aluminum carbide). For metals with variable oxidation states, Roman numerals are used (e.g., $Fe_2(SO_4)_3$ is Iron (III) sulfate). Covalent compounds use Greek prefixes to denote atom counts: 1 (mono), 2 (di), 3 (tri), 4 (tetra), 5 (penta), 6 (hexa), 7 (hepta), 8 (octa), 9 (nona), 10 (deka).

Van der Waals forces include: Dipol-Dipol (between permanent dipoles in polar molecules), Ion-Dipol (between ions and polar molecules), and London Dispersion Forces (temporary induced dipoles, occurring in all molecules but dominant in apolar ones). Hydrogen bonding is a specific, stronger weak interaction occurring when hydrogen is bonded to $F$, $O$, or $N$.

Physical and Chemical Changes and States of Matter

Physical changes involve state changes (melting, freezing), dissolving of salt/sugar, or metal conductivity. Chemical changes involve reactions like rusting, combustion, fermentation, digestion, and photosynthesis.

Matter exists in four states: Solids (regular arrangement, vibration only, Amorphous vs. Crystal), Liquids (fluid, volume but no shape, viscosity), Gases (highly compressible, high disorder, fill container), and Plasma (ionized gas containing ions and free electrons). Viscosity is the resistance of a liquid to flow and is inversely proportional to temperature.

Chemical Laws and the Mole Concept

The Law of Conservation of Mass states that the total mass of reactants equals the total mass of products. The Law of Definite Proportions (Proust) states that elements in a compound always combine in a fixed mass ratio. The Law of Multiple Proportions (Dalton) states that when two elements form multiple compounds, the masses of one element combining with a fixed mass of the other are in a simple whole-number ratio (e.g., $N_2O_3$ and $N_2O_5$ have an oxygen ratio of $3:5$).

The mole is defined by Avogadro's number ($N_A = 6.02 \times 10^{23}$). Relative atomic mass is based on Carbon-12. One atomic mass unit ($akb$) is $1/12th$ the mass of a $C_{12}$ atom. One mole of gas at Normal Conditions ($0^\circ C$, $1\,atm$) occupies $22.4\,dm^3$. At Standard Conditions ($25^\circ C$, $1\,atm$), it occupies $24.5\,dm^3$.

Mixtures, Concentration, and Separation

Mixtures are physical combinations of substances. Homogenous mixtures (solutions) appear as a single phase. Heterogeneous mixtures include Suspensions (solid-liquid), Emulsions (liquid-liquid), Aerosols (solid/liquid in gas), Colloids (fine particles in liquid), and Adi Mixtures (large solid particles). Concentration is measured by mass percentage, volume percentage, or parts per million ($ppm$). For $ppm$, $1\,ppm = 1\,mg/kg$. Colligative properties like boiling point elevation and freezing point depression depend solely on the concentration of dissolved particles.

Separation techniques include: Density-based (using a separatory funnel for immiscible liquids like oil/water or flotation/flokasyon for ores); Size-based (sieving, filtration, dialysis); and Point-based (Simple distillation for solid-liquid solutions, Fractional distillation for liquid-liquid solutions with different boiling points, and Crystallization for solubility differences).

Acids, Bases, and Salts

Acids release $H^+$ ions in water, taste sour, turn litmus paper red, and have $pH < 7$. Bases release $OH^-$ ions, taste bitter, feel slippery, turn litmus paper blue, and have $pH > 7$. Neutralization reactions occur when an acid and base react to form salt and water ($\\text{Acid} + \\text{Base} \\rightarrow \\text{Salt} + \\text{Water}$).

Metal reactivity varies: Active metals react with acids to produce $H_2$ gas. Semi-noble metals ($Cu$, $Hg$, $Ag$) react with oxidizing acids like $H_2SO_4$ or $HNO_3$ to produce gases such as $SO_2$, $NO_2$, or $NO$. Noble metals ($Pt$, $Au$) only react with Aqua Regia ("Kral Suyu"). Amphoteric metals ($Zn$, $Cr$, $Al$, $Sn$, $Pb$, $Be$) react with both acids and strong bases to release $H_2$ gas. Salts like $NaCl$, $Na_2CO_3$, $NaHCO_3$, and $CaCO_3$ are ionic crystalline products of these reactions.