Science Exam

Pure substances - Elements

Substances that can't be broken down further (Periodic Table)

Compounds

Substances made from 2 or more elements

Mixtures - Mechanical

Heterogeneous mixtures where different matters are visible, e.g., salad

Solutions

Homogeneous mixtures where different substances are not visible, e.g., apple juice

Chemical changes

Processes where the original substance changes into others with different properties

Qualitative physical properties

Properties described with words, e.g., color, texture

Quantitative physical properties

Properties measured with numbers, e.g., melting point

Chemical properties

Properties like combustibility, flammability, reactivity with acid

Dalton's atomic model

Represented atoms as billiard balls

Thomson's atomic model

Represented atoms as plum pudding

Rutherford's atomic model

Represented atoms with a nuclear structure

Bohr's atomic model

Represented atoms with electrons orbiting like planets

Isotopes

Atoms of the same element with different neutrons, affecting mass

Atomic number, mass, notation

AN = protons, AM = protons + neutrons, SAN = mass on top left, AN on bottom left, symbol in center

Conductors vs

Conductors transfer electrons well, insulators do not

Grounding

Connecting a conductor to Earth to transfer excess electrons

Cations & anions

Cations lose electrons (+), anions gain electrons (-)

Herbivore, carnivore, omnivore, producer, niche

Different roles in ecosystems

Mutualism, commensalism, ammensalism, predation, parasitism

Different species interactions

Biotic & abiotic factors

Living vs. non-living components in ecosystems