Grade 8: Properties of Materials - Atoms, Elements, and Compounds

Atomic number is the number of protons in an atom, unique for each element, while mass number is the sum of protons and neutrons in the nucleus.

Noble gases have a full outer electron shell, making them very stable.

Ionic bonds are formed when atoms gain or lose electrons to become charged ions, while covalent bonds are formed when atoms share electrons.

<p>As you move down the group, the properties of halogens change, with the color darkening and the elements becoming more reactive.</p> Signup and view all the answers

<p>Protons are positively charged particles in the nucleus of an atom.</p> Signup and view all the answers

<p>Ionic compounds are made from metals and non-metals reacting together, while covalent compounds are made from non-metal atoms sharing electrons.</p> Signup and view all the answers

<p>Heat is the total thermal energy in an object, measured in Joules, while temperature is the average energy of particles in an object, measured in Kelvin, Celsius, Reaumur, or Fahrenheit.</p> Signup and view all the answers

<p>Conduction (in solids), convection (in fluids), and radiation (through electromagnetic waves).</p> Signup and view all the answers

<p>The first shell can hold a maximum of 2 electrons.</p> Signup and view all the answers

<p>Alkali metals produce alkalis when reacting with water.</p> Signup and view all the answers

<p>The total energy in the universe remains constant.</p> Signup and view all the answers

<p>To show the flow of energy through a device or process.</p> Signup and view all the answers

<p>Efficiency = (Useful energy / Total energy) x 100%</p> Signup and view all the answers

<p>Dissipation is when thermal energy moves from a hotter place to a colder place, and the energy spreads out and moves to a colder place.</p> Signup and view all the answers

<p>Through the vibration of particles that are close together in solids.</p> Signup and view all the answers

<p>Kilojoules (kJ)</p> Signup and view all the answers

<p>Convection is the transfer of heat in fluids where particles move around.</p> Signup and view all the answers

<p>Xylem vessels form empty tubes for water transport throughout the plant.</p> Signup and view all the answers

<p>Transpiration is the loss of water vapor from plant leaves. When a plant loses too much water, it becomes wilted, causing leaves and soft tissues to flop over.</p> Signup and view all the answers

<p>The three main functions of water in plants are: 1) Support, 2) Transport, and 3) Cooling.</p> Signup and view all the answers

<p>Folic acid helps reduce the risk of neural tube defects (birth defects of the brain and spinal cord) in the fetus.</p> Signup and view all the answers

<p>Protein is necessary for the fetus to produce new cells and grow.</p> Signup and view all the answers

<p>Carbohydrates supply energy to the fetus.</p> Signup and view all the answers

<p>Iron is essential for producing hemoglobin.</p> Signup and view all the answers

<p>Calcium helps the baby develop strong bones and maintains the mother's bone and teeth health.</p> Signup and view all the answers

<p>It reduces the oxygen transport capacity of hemoglobin, leading to less oxygen for the fetus's cells and impaired growth.</p> Signup and view all the answers

<p>It is a list of metals arranged by their reactivity, from most reactive at the top to least reactive at the bottom.</p> Signup and view all the answers

<p>A more reactive metal displaces a less reactive one from its compound.</p> Signup and view all the answers

<p>It is exothermic, releasing a large amount of heat.</p> Signup and view all the answers

<p>Carbon can displace metals like zinc, iron, tin, and lead from their oxides.</p> Signup and view all the answers

<p>A salt is formed when a metal reacts with an acid.</p> Signup and view all the answers

<p>Metals with hydrochloric acid produce metal chlorides and hydrogen.</p> Signup and view all the answers

<p>The reactivity series can be used to predict whether a metal will react with a metal oxide or a metal sulfate solution by comparing the positions of the metals in the series. A more reactive metal will displace a less reactive metal from its oxide or sulfate solution.</p> Signup and view all the answers

<p>When a metal carbonate reacts with an acid, it produces a salt, water, and carbon dioxide.</p> Signup and view all the answers

<p>The law of conservation of mass states that the mass of reactants equals the mass of products in a chemical reaction. This means that matter cannot be created or destroyed, only transformed.</p> Signup and view all the answers

<p>Conducting displacement reactions with various metals helps to predict and understand how different metals react with metal oxides and metal sulfate solutions based on the reactivity series.</p> Signup and view all the answers

<p>Sound is a form of energy transferred as longitudinal waves, produced by vibrating sources in a medium (solid, liquid, gas).</p> Signup and view all the answers

<p>The main point of studying displacement reactions using the reactivity series is to predict and understand how different metals react with metal oxides and metal sulfate solutions.</p> Signup and view all the answers

<p>The reactivity series is significant in understanding displacement reactions because it allows us to predict which metals will react with metal oxides and metal sulfate solutions.</p> Signup and view all the answers

<p>Understanding neutralization reactions is important because it allows us to understand how acids and bases react to form salts and water.</p> Signup and view all the answers