Science 8 T2 Final Term Exam Reviewer PDF

Science 8 T2 Final Term Examination Reviewer | Part 1 ™ Made by: Matteo Zalvidea, Railey Jacob P. See, and Zaeiouz Hierco, of 8D/E —————————————————————————————————————————————— Table of Contents: ​ Lesson 1: Properties of Matter ​ Lesson 2: Phases of Matter...

Science 8 T2 Final Term Examination Reviewer | Part 1 ™ Made by: Matteo Zalvidea, Railey Jacob P. See, and Zaeiouz Hierco, of 8D/E —————————————————————————————————————————————— Table of Contents: ​ Lesson 1: Properties of Matter ​ Lesson 2: Phases of Matter ​ Lesson 3: The Atomic Theory of Matter ​ Lesson 4: Ions and Isotopes ​ Lesson 5: Electron Configuration ————————————————————————— Classifications of Matter Lesson 1: Properties of Matter pp. 193-203 1.​ Pure Substance: is made up of only 1 ————————————————————————— particle and has fixed composition and consistent properties. Pure substances ​ Subchapter 1: Fundamental Concepts! have 2 types: A.​ Element: A pure substance made Atoms and Molecules up of only one kind of atom. -​ The building blocks of matter that make up everything. Ex: Oxygen on its own. B.​ Compound: Combination of two or Matter more elements. -​ It has mass and occupies space (volume). Ex: Water, is made up of two hydrogen atoms -​ It can be classified as: elements or and one atom of oxygen. compounds. ​ It is also a molecule as two or more -​ Made of atoms that keep their chemical atoms form it. properties until they change a chemical reaction. Note: Not all molecules are compounds like oxygen. ➔​ Elements and Compounds: Both ​ Molecule: Made up of two oxygen atoms. substances. ​ Compound: Not a compound as it is solely made of oxygen. ​ Subchapter 2: Introduction to Atoms 2. ​ Mixture: a combination of 2 or more Atoms: compounds A.​ Homogeneous: Uniform Composition. Only has 1 phase. B.​ Heterogeneous: Non-Uniform Composition. Usually has visible particles in the mixture. ​ Subchapter 4: Properties of Matter Property Smallest thing: Quarks (building blocks of -​ An observable characteristic that protons and neutrons) describes an object or a substance. Atoms: Made up of electrons, protons, and neutrons. ​ Subchapter 5: Physical Properties of ​ Subchapter 3: Classifications of Matter Matter Physical Properties Texture Feel of substance when -​ It may be observed or measured without touched. changing the chemical composition of a substance. Durability Ability to resist corrosion. 1.​ Extensive: Depend on the amount or size Brittleness The ability of an object to break of the substance. apart or shatter easily. ➔​ The property changes when the quantity of the object changes. Elasticity The ability of the material to return to its original shape after being stretched/compressed. Extensive Description: Properties of Temperature Amount of energy in a Matter: substance. Mass Amount of matter in the Conductor of The ability of a material to allow sample. heat and heat or electricity to flow in it. electricity Volume Space occupied by the substance. Boiling Point Temperature at which a substance boils Length The extent of the substance in one dimension. Melting Temperature at Point which a substance melts Weight Force exerted on an object due to gravity Physical Changes: Observable changes in the Size Physical appearance or physical property of matter. Does dimensions (length, width, not change into a new substance™. height, volume, etc.) of an ➔​ These changes may be irreversible and object. caused by folding, cutting, grinding, etc. 2.​ Intensive: Physical properties of matter ​ Subchapter 6: Chemical Properties of that are inherent to the substance and Matter remain unchanged. Chemical Change -​ Involves chemical reactions that result in Intensive Description: the formation of new substances or Properties of products. Matter: Chemical Property Color Pigment of a substance. -​ The ability of a substance to undergo Odor Smell of a substance. chemical changes to become a different type of matter. Luster How matter reflects light. Malleability How objects are hammered into thin sheets. Ductility How matter can be stretched into thin wires? Hardness How matter can be scratched or dented? Viscosity How liquids easily flow.  ➔​ Solid: Definite volume, distinct space, compact molecules. Movement is confined to simple vibrations. Kinetic energy is so low the attraction of the molecules is stronger than the force pulling them apart. (Molecules and Elements are on the right and compounds are on the left.) Ice: A solid form of water, but it must have a temperature below 0°C to remain at this phase. ​ Oxidation: Chemical reaction to oxygen, This phase of the ice can be considered as solid. usually causes rusting. ➔​ Reactivity with oxygen (e.g., iron ➔​ Liquid: Definite volume, takes the shape of rusting when exposed to oxygen). the container, slightly packed molecules, ​ Reactivity: Ability to react with other more kinetic energy, and a weaker substances. molecular force than solids. ➔​ Reactivity with acids or bases (e.g., The molecules in a liquid have enough kinetic baking soda reacting with vinegar) energy to move fast to break out from their ​ Flammability: Ability to burn within the confined structure so they can move loosely as presence of oxygen. compared to the molecules in a solid. ➔​ Gasoline is highly flammable. ​ Toxicity: Ability of a substance to harm/kill ➔​ Gas: Dependent on temperature and ➔​ Cyanide is highly toxic. surround pressure. Molecules spread out ————————————————————————— into the environment. Has no definite Lesson 2: Phases of Matter pp. 204-216 shape nor volume, weak molecular force ————————————————————————— due to the farness of gaseous particles, highest kinetic energy, and distant and ​ Subchapter 1: Phases Changes! more energetic molecules moving in constant and random directions. Phase Change: Change of state by absorbing or The particles continuously collide with one releasing heat. another, which will then transfer the energy ➔​ They behave in such a way that their from one molecule to the other and vice versa. characteristics are affected by the motion of molecules. ➔​ Plasma: Particles gain through heating at ➔​ The higher the temperature, the greater very high temperatures or when they the kinetic energy resulting in faster absorb electric energy. Can return to gas movement. when losing kinetic energy. No volume, no definite shape, contains electrichargere. Water -​ Water is one of the basic needs of living Ionization: Atoms of an element break, allowing things. electrons to be free from the nucleus of the atom, -​ About 75 percent of our planet is covered leaving a positively charged atom. by water, which comes in different forms - ➔​ The process by which an atom or solid (glaciers), liquid ( natural water,) or molecule gains or loses electrons, gas (water vapor). resulting in an electrically charged atom -​ The water on the surface of Earth is or molecule called an ion. constantly changing among these phases. -​ This is an endless process that connects all Deionization: However, as the high temperature of these phases of water. that forms plasma falls, the electrons will then ​ Subchapter 1: Introduction to the Atom begin to return to the atom, forming back as a gas. Atom: Considered the smallest particle of matter that still has the properties of an element. ➔​ Bose-Einstein Condensate: Considered to be the exact opposite of plasma. It exists a Atomic Model: A representation of what an atom extremely low temperature or near could look like based on observations and absolute zero temperatures. It is one big scientific evidence. supergiant atom. It’s so cold (causing cold ng crush mo) that its ​ Subchapter 2: Parts of an Atom particles overlap and act as one single quantum entity. Gaseous Superfluid: As the atoms start to cool down they clump together to a state that they can no longer move or vibrate at all. ​ Subchapter 2: Phases of Matter! ​ Nucleus: Dense center of an atom ​ Melting: Occurs when heat is added to a solid, turning it into a liquid. containing protons (positively charged) ​ Freezing: This happens when a liquid and neutrons (neutrally charged) loses heat and becomes solid. ​ Electrons: Tiny particles moving around ​ Evaporation: (including boiling) occurs the nucleus in an electron cloud. They are when heat is added to a liquid, converting negatively charged. it into a gas. ​ Condensation: This happens when gas loses heat and turns back into a liquid ​ Subchapter 3: Pioneers of the Atomic ​ Sublimation: Where a solid directly Theory transitions to gas. Deposition is the reverse process where gas turns directly into a 1.​ Democritus (2400 B.C) solid -​ Who speculated that all matter is composed of tiny, indivisible particles he Cause: The absorbed heat is used to break the called "atoms" intermolecular bonds holding the solid together, resulting in a phase change. “Atomos” Meaning uncuttable or indivisible. According to him, these particles were eternal, ​ Subchapter 3: Phase Diagram indivisible, and varied in shape and size depending on the type of matter. Phase Diagram -​ Graph that shows the physical states of a 1.​ All things are composed of atoms that are substance under different conditions of too small to be seen by the naked eye and temperature and pressure. cannot be broken down further. -​ Typically, pressure is plotted on the 2.​ There are empty spaces between these (vertical) y-axis and temperature on the inner structures. (horizontal) x-axis. 3.​ Matter is made up of solid particles. 4.​ The matter has a uniform structure ➔​ Critical Point: The temperature at throughout. and above in which the vapor of 5.​ Matter varies in shape, size, and weight. the substance can't be liquefied no matter the pressure applied 2.​ Aristotle 2400 B.C) -​ He is the reason Democritus ideas were ————————————————————————— not widely accepted due to his being more Lesson 3: The Atomic Theory pp. 217-232 famous and influential. —————————————————————————  -​ He believed matter was made up of four Subatomic Particles: Challenged the theory natural elements and the ratio of these made by Dalton. It is a particle smaller than an four affects the properties of matter and atom. can be transformed into one another. The properties of substances depend on the balance of four qualities: hot, cold, wet, and 4.​ JJ. Thompson (1897) dry. -​ Using a cathode ray tube, found evidence for the electron, a tiny, negatively charged Aether: He believes in what makes up the model. heavens and celestial bodies. -​ He expected the beam of light will travel in a straight line, however in the presence of 3.​ John Dalton (1808 AD) oppositely charged plates, it was attracted -​ An English physicist whose findings were to the positively charged plate and written in a book called A New System of deflected from the negatively charged one. Chemical Philosophy. -​ He believed atoms had four Conclusion: He deduced the beam of light must characteristics. be made up of negatively charged particles which he called electrons. Cathode Ray Tube: A vacuum tube containing a partially evacuated glass tube with electrodes at either end, through which an electric current can pass. ➔​ When high voltage is applied, it generates streams of electrons, known Solid Sphere/BIlliard Ball Model: Atoms were as cathode rays, moving from the small, indivisible spheres, each unique to a cathode (-) to the anode (+) specific element. Plum Pudding Model -​ A model in which electrons were embedded within a diffuse, positively charged sphere. -​ This is then held by the attractive forces between the two. ​ ◆​ Law of Definite Proportions: He observed that certain substances combined in fixed proportions by mass to form compounds. Example: For instance, water always consists of 2 parts hydrogen and 16 parts oxygen by mass which states that when two elements form more than one compound (water as it is). 5.​ Ernest Rutherford (1909) -​ Conducted the now-famous gold foil 1.​ Atoms are tiny invisible particles experiment where he directed alpha 2.​ The atoms of an element are all the particles at a thin sheet of gold foil. same. 3.​ The atoms of different elements vary from Gold Foil Experiment: He used alpha particles one another. emitted from a radioactive atom to bombard 4.​ Atoms may form compounds if combined. ultrathin gold foil and detect the particles using a screen. He expected these particles to pass through, however it showed some particles ​ bouncing off. Conclusion: He concluded that an atom has a dense center which he called the nucleus with a 7.​ James Chadwick (1932) positive charge in it called the protons while -​ There was a mystery in the atomic model. electrons surround the nucleus. The masses of many atoms were found to be greater than the total mass of their Nuclear Model: A nucleus made up of protons in protons and electrons combined. the center surrounded by electrons. -​ This suggested the existence of an ​ additional particle. -​ Chadwick observed that when beryllium was bombarded with alpha particles, it emitted a mysterious type of radiation. Conclusion: Chadwick hypothesized that this radiation was composed of neutral particles. This was called the neutron. Note: Neutral charge does not entirely mean there is no charge, it refers to an equal region of 6.​ Neils Bohr (1913) positive and negative charges. -​ Electrons can jump from lower energy levels to higher energy levels once they 8.​ Erwin Schrödinger and Werner absorb (absorption) or release (emission) Heisenberg (Present) energy from various forms such as heat, -​ The final evolution of atomic theory came light, or electricity. with the development of modern quantum mechanics in the 20th century. 1.​ Each energy level is at a certain distance -​ Introduced the Electron Cloud Model, away from the nucleus. which replaced the idea of fixed orbits with 2.​ The farther the distance of the energy probabilistic regions where electrons are levels, the greater the energy. most likely to be found. 3.​ Electrons can jump from lower → higher energy levels once they absorb enough energy. Planetary Model: Suggested that electrons orbit the nucleus with a fixed path and energy levels. ————————————————————————— ​ Subchapter 2: Ions and Isotopes Lesson 4: Ions and Isotopes pp. 226-232 ————————————————————————— Ions: An atom or molecule that has gained or lost one or more electrons, resulting in a net electrical ​ Subchapter 1: Atomic Numbers charge. Ions can be positively charged (cations) or negatively charged (anions). Atomic Numbers -​ An element is the number of protons found in the nucleus of an atom of that ➔​ Valence Shell: These are arranged element. It is denoted by the symbol Z. in energy levels (shells) around the -​ The number of protons in an atom is nucleus. The outermost shell. always equal to its atomic number (e.g. Carbon (C) has an atomic number of 6, so it I.​ Cations: Formed when an atom loses has 6 protons). electrons. In a neutral atom: The number of electrons is II.​ Anions: Formed when an atom gains equal to the number of protons because the electrons. negative charge of electrons balances the positive charge of protons. Isotopes: These are atoms of the same element that have the same number of protons (and thus Chemical Number the same atomic number) but different numbers -​ An element name is a unique name given of neutrons in their nuclei. Form naturally or to a chemical element, which represents a pure substance consisting of atoms with through nuclear reactions, where neutrons the same number of protons in their change due to nuclear decay. nucleus (the atomic number). Represented by the symbol X. ➔​ Half-Life: The time it takes for half of a given sample of a particular isotope to decay on average. ​ Subchapter 3: Equation Chemical Symbol -​ A chemical symbol is a shorthand The neutron number is the difference representation of a chemical element, between the mass number and the atomic consisting of one or two letters derived number. It is calculated using the formula: from the element's name, often in Latin N = A-Z or English. The mass number is the total number of protons and neutrons in an atom's nucleus. It is calculated using the formula A = Z+N Atomic Mass ————————————————————————— -​ (also known as atomic weight) is the Lesson 5: The Electron Configuration pp. average mass of an atom of an element, 233-244 represented by the symbol A. -​ It accounts for the mass of protons, ————————————————————————— neutrons, and electrons in an atom, but the electron mass is so small it is usually ​ Subchapter 1: Configurate your Mind! negligible. Electron Cloud Model -​ Known as the Quantum Mechanical Model of the Atom is the modern model/diagram/representation of the atom that we have at present. -​ States that the center of the atom is the nucleus, which contains protons (positively  charged particles) and neutrons (neutral The larger the value of n: The farter it is away particles). from the nucleus, and thus the higher the energy of an electron. Electron Configuration Angular Momentum Quantum Number -​ Used to describe and show the distribution -​ Represents the shape of the sublevel in of electrons in each energy level located in earache energy level, which may be various locations or orbitals. expressed from 0 to (n - 1). -​ Describes the orbitals of an atom in its -​ The secondary quantum number divides ground state, but it can also be used to the energy level or shell into smaller represent an atom that has been ionized groups of orbitals. into a cation or an anion. ​ Subshells/Sublevels -​ When a group of orbitals are in the Electron Cloud same shape. -​ Region in the atom where electrons may be found, or where the electrons are most likely to be found at a given time. -​ The bigger the cloud, the more electrons. Magnetic Quantum Numbers -​ Describes the orientation in space of an orbital of a given energy (n) and shape (l). -​ This number divides the subshell into individual orbitals that hold the electrons. ​ Subchapter 2: Quantum Numbers Spin Quantum Number -​ Describes the spin of an electron in an Quantum Numbers orbital. An electron can spin only in two -​ A value that is used when describing the directions, which is either clockwise (m = energy levels of electrons in atoms. +½) or counterclockwise (m = -½) Atomic Orbitals ​ Subchapter 3: Orbitals -​ A region of space in which there is a high chance of finding electrons. Orbitals -​ Energy changes within an atom as a result -​ The orbitals have a maximum capacity of of an electron changing from a wave electrons to hold (s, p, d, f) and their pattern with one energy to a wave pattern capacities: with different energies. 1.​ s: 2 electrons 2.​ p: 6 electrons Principle Quantum Numbers 3.​ d: 10 electrons -​ Specifies the energy of an electron the size 4.​ f: 14 electrons of the orbital and its distance away from the nucleus. Note: We all know that atomic number is equal to -​ All orbitals that have the same value of n the number of protons and electrons in a neutral are said to batin the same level. atom. ➔​ Therefore, the number of electrons that Represented by: Whole numbers. If n = 1, then it dictates the configuration is the same means the electrons os/are found in the first as the atomic number. energy. ➔​ If n =2, then it means that the electron is Orbital Diagrams found at the second energy level, and so -​ Pictorial representations of the electrons in on. an atom.  -​ Shows the distribution of electrons in each orbital. Consists of a box for each orbital 3.​ Hund’s Rule with an arrow representing an atom and -​ This rule states that every orbital of the its two spins. same energy must be singly occupied with -​ The different directions of the arrows show one electron before any orbital is doubly the difference of electrons in the same occupied. orbital. -​ Fill in all of the empty orbitals before -​ Each arrow represents an orbital. pairing. How to Write the Electron Configuration of an Element 1.​ Determine the atomic number of the element. Remember that in a neutral atom, the atomic number is also equal to the number of electrons. 2.​ Fill the sublevel with the superscript that shows its number of electrons. 3.​ Do not forget to take into consideration ​ Subchapter 4: Principles the maximum number of electrons in each sublevel. Principles: There are principles that govern the 4.​ After the sublevel 3p, the sequence of the electron configuration. These principles are used electron configuration varies so you need to determine the correct configuration for to be familiar with the order of the orbitals. elements. __________________________________________________ References: 1.​ Aufbau Principle Science 8 T2 Notes -​ States that a lower energy orbital should Science 8 T2 | Atomic Theory, Ions and Isotopes, be filed first before the next higher energy Electron Configuration orbital. Science 8 T2 | Properties of Matter -​ Assumes that electrons are added to an Science 8 T2 | Phases of Matter atom, one at a time, starting with the lowest energy orbital until all of the electrons have been placed in an appropriate orbital. -​ The arrangement of orbital energy is as follows: s < p < d < f. Electrons occupy the lowest energy orbital available. For Hydrogen (1 electron) - The first electron goes into the lowest energy orbital 1s. For Helium (2 electrons) - Both electrons fill the 1s orbital because it’s the lowest energy level. 2.​ Pauli Exclusion Principle -​ No two electrons can have exactly the same set of quantum numbers. Note: The set of quantum numbers for a specific electron is unique for that electron alone. -​ If an electron has the same n, l, or m, values, this means that tit occupies the same energy level and the same subshell or orbital. -​ Only two electrons can fit into a single orbital. For Helium (2 electrons) - The 1s orbital has two electrons, but one spins up (↑) and the other spins down (↓), so its orbital diagram is 1s ↑↓