Uncuttable

- Components are NOT distinguishable (single phase) - Have same composition throughout (i.e. same amount in any areas - e.g. SOLUTION

- the smallest unit that retains the properties of an element.

- Fixed composition (e.g. 100% ethanol) - Cannot be separated into simpler substances by physical methods

anything that has mass and occupies space

- Independent on the amount of substance - e.g. DENSITY, Electrical Conductivity

- Components are distinguishable (multiple phases) - Do NOT have same composition throughout (i.e. different amount in various areas - e.g. SUSPENSION

Who described the electron of a hydrogen atom as revolving around its nucleus in one of a discrete set of circular orbits. • ____ Planetary Model - Each orbit thus corresponds to a definite energy level for the electron. - When an electron is excited from a lower energy level to a higher one, it absorbs a definite (quantized) amount of energy. - Electrons occupy only certain energy levels in atoms.

- no change in chemical composition - REVERSIBLE - e.g. shredding paper, boiling of water, breaking a bottle

Found Solid Sphere (Billiard Ball) Model - Atom as solid sphere but NOT indivisible (with year)

- Cannot be decomposed to simpler substance by chemical changes - Consists of only one kind of atom

Energy Changes: Release (heat)

Gas to Liquid

Liquid to solid

- can be observed or measured without changing the identity of the substance. - e.g. color, hardness, melting point, boiling point

Energy in motion

the capacity to do work or to transfer heat

Hydrocarbons and its derivatives

_______ are atoms of the same element with different masses. • They are atoms containing the same number of protons but different numbers of neutrons.

Who said the Elements of a chemical compound are held together by Electrical forces (wih year)

Variable Composition (e.g. 70%, 80% or 95% ethanol in water) - May be separated into pure substances by physical methods (e.g. distillation, filtration)

Energy Changes: absorbs (heat)

amount of space

Detection and identification of substances present (qualitative analysis) or amount of each substance (quantitative analysis)

Gas to solid

Elements of a chemical compound are held together by_____

Found Electrons" → Electric ions with year

Solid to gas

- one or more substances are used up - one or more new substances are formed, - energy is absorbed or released - IRREVERSIBLE - e.g. burning of paper, cooking an egg, souring of milk

Represents the composition of the nucleus

Who studied X-rays given off by various elements. - "The number of PROTONS in the nucleus of an atom determines its identity; this number is known as the ATOMIC NUMBER of that element. WITH YEAR

Found Relationship between the amount of electricity used in electrolysis and the amount of chemical reaction that occurs (with year)

Behavior of matter

Processes in living organisms

Theory All matter is composed of atoms and these cannot be made or destroyed.

found The Scattering Experiment WITH YEAR

Dependent on the amount of substance - e.g. MASS - more substance, greater mass - e.g. VOLUME - more substance, greater volume

Who Oil-drop Experiment WITH YEAR

Who Cathode-Ray Tube Experiment WITH YEAR

Found The Discovery of Protons • Canal Rays Experiment (With year)

Experiment - Most convincing evidence of electrons - Plum pudding model- Most convincing evidence of electrons - Plum pudding model

Liquid to gas

the science that describes matter-its properties, the changes it undergoes, and the energy changes that accompany those processes.

Energy at rest

Found Saturn-like model WITH YEAR

measure of the quantity of matter

- Can be decomposed to simpler substance by chemical changes - consists of atoms of two or more different elements bound together. - e.g. water, H20 can be broken into hydrogen and oxygen gases via electrolysis

exhibited by matter as it undergoes changes in composition. - e.g. hydrogen has the potential to ignite and explode given the right conditions - e.g. iron reacts with oxygen gas to form rust

Who said Matter is made up of four elements

The Wave Nature of Electron • _________ - proposed the idea of wave-like nature of electrons • Electrons can be treated as waves more effectively than as small compact particles traveling in circular or elliptical orbits.

Inorganic compounds, metals, minerals

_____ as solid indivisible sphere

Solid to liquid