Sem 2 Revision QUIZ - Chemistry & Biology

Chemistry -Atoms: The Building Blocks of Matter History of Discovery: Scientists like Dalton, Thomson, Rutherford, and Bohr helped us understand the atom's structure over time. Atomic Structure: Atoms are made up of tiny particles called protons, neutrons, and electrons....

Chemistry -Atoms: The Building Blocks of Matter History of Discovery: Scientists like Dalton, Thomson, Rutherford, and Bohr helped us understand the atom's structure over time. Atomic Structure: Atoms are made up of tiny particles called protons, neutrons, and electrons. o Protons: Positively charged particles in the nucleus. o Electrons: Negatively charged particles orbiting the nucleus. Periodic Table: Elements are arranged in rows (periods) and columns (groups) based on their properties. o Atomic Number: The number of protons in an atom's nucleus. o Mass Number: The total number of protons and neutrons in an atom's nucleus. Electron Configuration: Electrons orbit the nucleus in shells. The first shell can hold 2 electrons, the second shell can hold 8, and so on. Ions: Atoms that have gained or lost electrons. o Cations: Positively charged ions (lost electrons). o Anions: Negatively charged ions (gained electrons). Chemical Reactions Reactants and Products: Reactants are the starting substances, and products are the substances formed. Law of Conservation of Mass: Matter cannot be created or destroyed, only transformed. Balancing Equations: To ensure mass is conserved, the number of atoms of each element must be the same on both sides of the equation. Exothermic and Endothermic Reactions: Exothermic reactions release energy, while endothermic reactions absorb energy. Acids and Bases Acids: Sour-tasting substances that turn blue litmus paper red. Bases: Bitter-tasting substances that turn red litmus paper blue. Neutral Substances: Substances that are neither acidic nor basic, like water. pH Scale: Measures acidity and basicity, with 7 being neutral. Neutralization: An acid and a base react to form a salt and water Biology The Nervous System Central Nervous System (CNS): Composed of the brain and spinal cord. o Brain: Controls thoughts, emotions, and body functions. o Spinal Cord: Connects the brain to the rest of the body. Peripheral Nervous System (PNS): Connects the CNS to the rest of the body. o Somatic Nervous System: Controls voluntary actions. o Autonomic Nervous System: Controls involuntary actions. Neurons: Nerve cells that transmit electrical signals. o Parts of a Neuron: Cell body, dendrites, and axon. Synapse: The gap between neurons where nerve impulses are transmitted. Reflex Arc: A simple, automatic response to a stimulus. The Endocrine System Hormones: Chemical messengers produced by glands. Pituitary Gland: The "master gland" that controls other glands. Thyroid Gland: Regulates metabolism. Adrenal Glands: Respond to stress. Pancreas: Regulates blood sugar levels. Homeostasis: The body's ability to maintain a stable internal environment.