Year 9 Science - Term 2 Revision Flashcards

Flashcards for Year 9 Science Term 2 Revision Sheet, focusing on Atomic Structure, Isotopes, Radioactivity, and Chemical Reactions.

Subatomic Particles

Particles located in the atom: protons (positive charge) and neutrons (no charge) in the nucleus, and electrons (negative charge) orbiting in electron shells.

Law of Conservation of Mass

The total mass of the reactants equals the total mass of the products.

Base

A substance with a pH greater than 7.

Neutralization Reaction

Reaction where an acid and a base react to form a salt and water; H+ + OH- -> H2O.

Comparison of Alpha, Beta, and Gamma Radiation

Alpha: Large mass, +2 charge, low penetrating ability. Beta: Small mass, -1 charge, medium penetrating ability. Gamma: No mass, no charge, high penetrating ability.

Half-life

The time taken for half of the radioactive atoms in a sample to decay.

Isotopes

Atoms of the same element with different numbers of neutrons and therefore different mass numbers.

Exothermic Reaction

A reaction that releases energy in the form of heat.

Endothermic Reaction

A reaction that absorbs energy from its surroundings.

Nucleus

The central part of an atom containing protons and neutrons; virtually all of the atom's mass is here.

Electron Shell

The area surrounding the nucleus where electrons are found.

Protons

Positively charged particles in the nucleus.

Neutrons

Neutral particles in the nucleus.

Electrons

Negatively charged particles orbiting the nucleus.

Electrical Neutrality of Atoms

Atoms are electrically neutral because they have an equal number of protons (positive charge) and electrons (negative charge).

Gamma Radiation

A form of electromagnetic radiation that is highly penetrating and can cause significant damage to living tissue.

Reactants

The substances initially involved in a chemical reaction.

Products

The substances that are formed as a result of a chemical reaction.

Conservation of Mass

The principle that states that mass is neither created nor destroyed in a chemical reaction

pH Scale

A scale used to specify the acidity or basicity of an aqueous solution.

Indicators

Substances that change color in the presence of an acid or a base.