SCIENCE TERM 1 EXAM

Electron

e- , orbits the nucleus

Proton

p+, identifies the atomic number

Neutron

n0, adds mass and stabilizes the nucleus

Atomic Number (Z)

Equals number of protons and electrons

Atomic Mass (A)

Total protons plus neutrons

Neutron Formula

n0 = A - Z

Valence Electron

Electron in the outermost shell

Stable Valence

8 valence electrons

Unstable Valence

1 valence electron

Isotopes

Atoms of the same element with different neutron numbers

Metal

Shiny, solid, ductile, malleable, good conductor

Nonmetal

Solid, liquid, or gas, dull, brittle if solid

Metalloid Examples

Boron, Silicon, Germanium, Arsenic, Antimony, Iodine

Alkali Metals

Soft, silvery, reactive, stored in oil

Alkaline Earth Metals

Less reactive, hard

Transition Metals

Middle of periodic table, e.g. copper, gold, silver

Halogens

Far right group, highly reactive, rarely pure

Noble Gases

Least reactive, stable

Octet Rule

Atoms gain, lose, or share electrons to get 8 valence electrons

Solid

Compressed particles

Liquid

Spaced particles

Gas

Widely spaced particles

Melting

Solid to liquid

Freezing

Liquid to solid

Sublimation

Solid to gas

Deposition

Gas to solid

Evaporation

Liquid to gas

Condensation

Gas to liquid

Leucippus & Democritus

First atomic theorists

Democritus

Proposed atoms (atomos), invisible, many shapes

Aristotle

Rejected Democritus' atomic theory

John Dalton

Elements have fixed ratio, revived atomos as sphere model

J.J. Thomson

Plum pudding model, discovered electron via cathode ray tube

Ernest Rutherford

Gold foil experiment, discovered proton and nucleus

James Chadwick

Beryllium radiation experiment, discovered neutron

Niels Bohr

Energy levels, planetary model

Erwin Schrodinger

Electron clouds, quantum mechanical model

Atom

Basic unit of matter

Subatomic Particle

Smaller than an atom

Nucleus

Central part of the atom

Electrostatic Forces

Attraction or repulsion between charged particles

Digestive System

Group of organs that break down food into usable nutrients

Mouth

Chews food, starts digestion

Esophagus

Muscular tube connecting mouth to stomach

Stomach

Breaks down food with hydrochloric acid and enzymes

Small Intestine

Longest part of digestive tract, absorbs nutrients into bloodstream

Large Intestine

Absorbs water and electrolytes, forms solid stool

Rectum

Stores feces before elimination

Anus

Eliminates solid waste from the body

Liver (digestive)

Produces bile to break down fats

Pancreas

Releases digestive enzymes, regulates blood sugar

Gallbladder

Stores and releases bile

Excretion

Removal of metabolic waste produced by body cells

Egestion

Removal of undigested food never absorbed by body cells

Urea

Waste from protein breakdown

Kidneys

Filter blood and produce urine

Nephrons

Tiny filtering units in kidneys, about 1 million per kidney

Filtration

Water, salts, urea, glucose forced from blood into nephron tubule

Reabsorption

Useful substances returned to blood from tubule fluid

Secretion

Extra wastes added to tubule fluid to form urine

Ureters

Tubes carrying urine from kidneys to bladder

Urinary Bladder

Stores urine until released

Urethra

Tube carrying urine out of the body

Lungs

Remove carbon dioxide and water vapor

Skin

Removes sweat, water, and salts

Liver (excretory)

Converts ammonia into urea, removes toxins from blood

Kidney Stones

Hard mineral deposits in the kidneys

UTI

Bacterial infection of bladder, urethra, or kidneys

Kidney Failure

Kidneys lose ability to filter waste from blood

Roots

Anchor the plant, absorb water and minerals

Stem

Supports plant, transports water, nutrients, food

Leaves

Site of photosynthesis

Flowers

Reproductive part, attracts pollinators

Fruits

Protect and disperse seeds

Seeds

Contain the embryo of a new plant

Xylem

Conducts water and minerals upward from roots

Phloem

Conducts sugars downward from leaves

Transpiration

Water absorbed by roots, released as vapor through leaves

Root Pressure

Upward push of sap from osmotic pressure in roots

Capillary Action

Liquid flow in narrow spaces without external force

Sieve Tube

Phloem cells that transport food materials

Vascular Bundle

Strand of xylem and phloem in stem or leaves

Translocation

Transport of soluble food from one plant part to another

Guard Cell

Regulates gas exchange and water loss at a stoma

Stomata

Tiny leaf pores for gas exchange

Genetics

Study of heredity and variation of inherited traits

Gregor Mendel

Austrian monk, Father of Modern Genetics, researched pea plants

Heredity

Passing of traits to the next generation

Mendel's Seven Traits

Flower color, seed shape, seed color, pod shape, pod color, flower position, stem length

Allele

Gene in a pair, capital if dominant, lowercase if recessive

Homozygous Dominant

TT

Homozygous Recessive

tt

Heterozygous

Tt

Genotype

An organism's allele pair

Phenotype

Observable physical traits

Monohybrid Cross

Cross involving a single trait, shown in a Punnett Square