1. Properties and Changes
Atoms and Elements
Properties and Changes

2. Scientific Terminology
Control – an event that is used as a constant and unchanging standard of comparison in scientific experimentation.
Variable - capable of being varied or changed; alterable
Hypothesis - A tentative explanation that accounts for a set of facts and can be tested by further investigation.
Trial - the act of trying, testing, or putting to the proof.

3. Nature of Matter Particle Theory of Matter
All matter is made up of tiny particles
Each pure substance has its own kind of particles
Particles attract each other
Particles are always moving
Particles at a higher temperature move faster on average than particles at a lower temperature

4. Nature of Matter
Scientific Model – particle theory is one example of a SM
It helps us to picture a process in nature we can not see directly.
Matter – solid, liquid, gas
or plasma

5. Nature of Matter
Physical change
No new substance is being formed

6. Chemical change
At least one new substance, with new properties, is formed.
If two of the following are true, then a chemical change has probably occurred:
Heat is absorbed or produced
Starting material is used up
New colour appears
Material with new properties forms
Gas bubbles form in a liquid
Grains of solid appear in liquid

7. Nature of Matter
Physical Properties – observed and measured without forming a new substance
Colour = for gases the colour is often clear
Density = amount of matter that occupies a certain space
Qualitative physical property
Described but not measured

8. Physical Vs. Chemical Change
Physical change in a substance doesn't change what the substance is.
Chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.

9. Physical Vs. Chemical Properties
Physical properties can be observed or measured without changing its chemical composition.
Examples of physical properties include color and density.
Chemical properties may only be observed by changing the chemical identity of a substance.
In other words, the only way to observe a chemical property is by performing a chemical reaction. Examples of chemical properties include reactivity and flammability.

10. Physical Vs. Chemical Properties

11. Mixtures Mixtures make up most of the matter in the world Solutions
Solvent – substance that does the dissolving
Solute – substance that dissolves
Water + Salt = Chemical change?
Properties have changed however they can still be separated

12. Meet the Elements Element symbols
Based on a lot of common names and used to simplify the process
Einsteinium, polonium, uranium
Format created in 1817 by Berzrelius for two reasons:
Provided standard symbols for all known elements
Showed how to create symbols for any new elements that might be discovered
P.182 Table 5.2

13. Electrons, Protons and Neutrons
Bohr Rutherford Diagram
Protons – place a P in the nucleus, # is the same as atomic number
Electrons – place dots in shells, # is the same as atomic number. Shells fill 2, 8, 8 in terms of # of electrons in each. Pair up electrons.
Neutrons – place an N in the nucleus, # is rounded atomic mass minus atomic number.

14. Chemical Formulas
Chemical Formula = uses symbols and numbers to represent the composition of a pure substance
Definite proportions
Molecule = smallest independent unit of a pure substance
Electrolysis separates water molecules as the added energy rips the molecules apart

15. Different kinds of elements
Metals = conduct electricity and heat, hammered into sheets (malleability), stretched into wires (ductility), shiny lustre, and are solids at room temperature.
Non-metals = Some are gases at room temp, not shiny, not stretched into wires, poor electricity and heat conductors
Metalloids = in-between a metal and a non-metal

16. Families of Metals Characteristics
Group 1  alkali metals
React rapidly with water to produce hydrogen
Group 17  halogens
Most reactive non-metals
Chlorine & Bromine can cause many serious problems
Na (very reactive) + Cl (very reactive) = NaCl (table salt)
Group 18  noble gases
Chemically calm
Calm = noble in historic times

17. Isotopes, Ions and Electron Dot Diagrams
Isotope – alternative form of an element
Some are stable (normal), some are radioactive
Ions – atoms that have a charge
The charge can be positive or negative
Electron Dot Diagram
Puts electrons around the element name. The only electrons used are the ones in the outer ring.