SNC1W Grade 9 Science Exam Review Flashcards

Vocabulary-style flashcards covering Chemistry, Physics, Biology, and Astronomy topics for the Grade 9 Science (SNC1W) exam.

Standard Atomic Notation

A way to describe an atom that includes the chemical symbol, the mass number ($A$) as a superscript, and the atomic number ($Z$) as a subscript.

Atomic Number ($Z$)

The number of protons in the nucleus of an atom, which identifies the element.

Mass Number ($A$)

The total number of protons and neutrons in the nucleus of an atom.

Calculation for Neutrons ($N$)

The formula used to find the number of neutrons in an atom: $N = A - Z$.

Isotopes

Atoms of the same element that have the same number of protons but a different number of neutrons.

Ion

A particle formed when an atom gains or loses electrons, resulting in a net electrical charge.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Valence Electrons

The electrons located in the outermost energy level (valence shell) of an atom.

Octet Rule

The tendency of atoms to gain, lose, or share electrons to achieve a stable outer shell of eight electrons.

Law of Electric Charges

The principle stating that like charges repel each other, opposite charges attract, and charged objects attract neutral objects.

Conduction

A charging method where a charged object touches a neutral object, resulting in the transfer of electrons and both objects having the same charge.

Induction

A charging method where a charged object is brought near a neutral object without touching, causing a shift in electrons.

Potential Difference ($\triangle V$)

Also known as voltage, it is the difference in electric potential energy per unit charge between two points in a circuit, measured in Volts ($V$).

Electrical Current ($I$)

The rate of flow of electric charge past a point in a circuit, measured in Amperes ($A$).

Resistance ($R$)

The opposition to the flow of electric current in a material, measured in Ohms (\text{\Omega}).

Ohm's Law

The mathematical relationship between current, voltage, and resistance: $I = \frac{\triangle V}{R}$.

Power Calculation ($P$)

The rate at which electrical energy is used, often calculated as part of $E = P \times T$ where $E$ is energy and $T$ is time.

Biotic Factors

The living components of an ecosystem, such as animals, plants, and bacteria.

Abiotic Factors

The non-living physical and chemical components of an ecosystem, such as nutrients, light, and water.

Mutualism

A type of species interaction where both organisms benefit from the relationship.

Commensalism

A type of species interaction where one organism benefits and the other is neither helped nor harmed.

Parasitism

A relationship where one organism (the parasite) benefits at the expense of another organism (the host).

Ten Percent Rule

The principle that only approximately $10\%$ of the energy at one trophic level is transferred to the next level.

Biomagnification

The process by which the concentration of a substance, such as a pesticide, increases as it moves up the food chain.

Extirpated

A species that no longer exists in a particular local area but still exists elsewhere in the world.

Keystone Species

A species that has a disproportionately large effect on its natural environment relative to its abundance.

Indicator Species

An organism whose presence, absence, or health reflects the specific environmental conditions of an ecosystem.

Nuclear Fusion

The process in the Sun's core where hydrogen atoms join to form helium, releasing vast amounts of energy.

Astronomical Unit ($AU$)

A unit of distance equal to the average distance between the Earth and the Sun, approximately $1.5 \times 10^8 \text{\,km}$.

Light Year

The distance that light travels in a vacuum in one year.

Rotation

The spinning of a celestial body, such as Earth, on its axis.

Revolution

The orbital motion of one celestial body around another, such as Earth's motion around the Sun.

Red Shift

An observation used as evidence for the expanding universe, where light from distant galaxies shifts toward the longer-wavelength end of the spectrum.

Big Bang Theory

The scientific theory describing the origin of the universe as a rapid expansion from a single point of high density and temperature.