Chemical Substances Nature and Components Unit 1 1 1 MATTER AND ITS CLASSIFICATION DEFINITION OF MATTER CLASSIFICATION OF MATTER PURE SUBSTANCES AND MIXTURES ELEMENTS COMPOUNDS AND MIXTURES STRUCTURE OF AN ATOM SUBATOMIC PARTICLES PROTONS NEUTRONS ELECTRONS 2 ATOMS MOLECULES AND IONS ATOMIC NUMBER MASS NUMBER AND ISOTOPES CONCEPT OF MOLECULES AND IONS 3 CHEMICAL REACTIONS DEFINITION OF A CHEMICAL REACTION TYPES OF CHEMICAL REACTIONS COMBINATION DECOMPOSITION DISPLACEMENT DOUBLE DISPLACEMENT CHEMICAL EQUATIONS AND BALANCING EQUATIONS 2 4 Acids Bases and Salts Properties of acids taste reaction with metals indicators Properties of bases taste slippery feel reaction with acids indicators pH scale and its importance Neutralization reactions Common salts and their uses 5 Metals and Non Metals Physical and chemical properties of metals Physical and chemical properties of non metals Metalloids and their characteristics 6 Carbon and its Compounds Bonding in carbon compounds covalent bonding Properties of carbon allotropes diamond graphite fullerenes Organic compounds and their importance Hydrocarbons alkanes alkenes alkynes Functional groups and their significance 7 Materials Metals and Non Metals Uses of metals in daily life Uses of non metals in daily life Comparison between metals and non metals regarding properties and uses 3 definitions and explanations for matter classification of matter into pure substances and mixtures and the concepts of elements compounds and mixtures 4 Matter is anything that has mass and occupies space It is composed of particles such as atoms molecules or ions Matter can exist in various states including solid liquid and gas based on the arrangement and motion of 1 Definition of Matter its particles 2 Classification of Matter a Pure Substances Matter can be classified into two main categories pure substances and mixtures Pure substances are composed of only one type of particle and have a fixed composition They cannot be separated into simpler substances by physical methods Elements are pure substances made up of only one type of atom They are represented by chemical symbols e g O for oxygen Na for sodium and cannot be broken down into simpler substances by chemical reactions i Elements 5 Compounds are pure substances composed of two or more elements chemically combined in fixed proportions They can be broken down into simpler substances elements or other compounds by chemical reactions Compounds have unique properties distinct from their constituent elements ii Compounds b Mixtures Mixtures are combinations of two or more substances that are physically mixed together but not chemically combined Mixtures can be separated into their individual components by physical methods Homogeneous mixtures have a uniform composition throughout with particles evenly distributed Examples i Homogeneous Mixtures Solutions include saltwater air and sugar dissolved in water ii Heterogeneous Mixtures Heterogeneous mixtures have non uniform compositions with visible boundaries between their components Examples include a mixture of sand and iron filings oil and water or a salad with various ingredients 6 the structure of an atom including its subatomic particles protons neutrons electrons atomic number mass number isotopes and the concepts of molecules and ions Atoms are the basic building blocks of matter and consist of three main subatomic particles 1 Structure of an Atom a Protons Positively charged particles found in the nucleus of the atom Each proton has a relative mass of approximately 1 atomic mass unit amu and a charge of 1 b Neutrons Neutral particles found in the nucleus of the atom Neutrons have a relative mass of approximately 1 amu but carry no electric charge charge of 0 c Electrons Negatively charged particles that orbit the nucleus of the atom in specific energy levels or shells Electrons have a much smaller mass compared to protons and neutrons about 1 1836 amu and each electron has a charge of 1 The number of protons in the nucleus determines the identity of the atom as it defines the element The number of electrons in a neutral atom is equal to the number of protons maintaining overall electrical neutrality Atomic Number Z The atomic number of an element is equal to the number of protons in the nucleus of its atom It uniquely identifies the element For example hydrogen has an atomic number of 1 indicating it has one proton in its 2 Atomic Number Mass Number and Isotopes 7 nucleus Mass Number A The mass number of an atom is the sum of its protons and neutrons in the nucleus It is represented by the symbol A For example carbon 12 has a mass number of 12 indicating it has 6 protons and 6 neutrons Isotopes Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons This results in variations in mass numbers for isotopes of the same element For example carbon 12 carbon 13 and carbon 14 are isotopes of carbon with 6 7 and 8 neutrons respectively Molecules Molecules are formed when two or more atoms chemically bond together through covalent bonds These atoms can be of the same element e g O2 oxygen gas or different elements e g H2O water Molecules retain their identity and properties distinct from their constituent atoms 3 Concept of Molecules and Ions Ions Ions are charged particles formed when atoms gain or lose electrons An atom that loses electrons becomes positively charged and is called a cation while an atom that gains electrons becomes negatively charged and is called an anion Ions can be formed from both atoms and molecules 8 the definition of a chemical reaction the types of chemical reactions and the concept of chemical equations A chemical reaction is a process in which one or more substances reactants undergo chemical changes to form new substances products with different properties During a chemical reaction chemical bonds are broken and new bonds are formed resulting in the rearrangement of atoms to create different molecules Chemical reactions can be classified into several types based on the nature of the reactants and products and balancing equations 1 Definition of a Chemical Reaction 2 Types of Chemical Reactions Some common types include a Combination Reaction A combination reaction occurs when two or more substances combine to form a single product The general form of a combination reaction is A B AB For example the reaction of hydrogen gas H2 with oxygen gas O2 to form water H2O is a combination