gr 10 pre-ib chemistry review

table of contents: physical and chemical properties, matter, atomic models, ionic and covalent bonding (single,double,triple)

physical property

property that describes the physical appearance and composition of a substance

examples of physical properties (pick 3, give 2 examples and definition if needed)

colour, taste, odour, clarity, density, lustre, malleability, ductility, ability to produce electric charge, texture, form, hardness, brittleness, viscosity

chemical property

a property that describes the ability of a substance to change into a new substance or substances.

examples of chemical properties

ability to burn (combustion), flash point (lowest temp. which a flammable liquid will ignite in air), behaviour in air, reaction with air, reacting to heating

matter

any substance that has mass or takes up space

types of matter

pure substance and mixture

types of pure substances (two examples)

element (92 naturally occurring) and compound

main types of mixtures

heterogeneous and homogeneous

types of heterogeneous mixtures

suspension, colloid, mechanical

suspension + example

a heterogeneous mixture that contains large particles that are visible, but will eventually settle (e.g. tea and water)

colloid + example

where very small particles of one substance are evenly distributed through another substance. do not settle and cannot be separated by filtration (e.g. ketchup or gelatine)

mechanical + example

where the different components are easily separated by physical means. usually large enough to be separate by sorting, sieving or magnet. (e.g. salad, pencil case)

heterogeneous mixture

components are not uniformly distributed and often able to physically separate into different part. each part of the mixture retains its own properties

homogeneous mixture + example

components are uniformly distributed. the composition is consistent and you cannot easily distinguish different parts. (e.g. salt dissolved in water/air)

solute + example

substance that dissolves into another substance to form a solution (e.g. salt)

solvent + example

dissolves another substance to form the solution and are typically liquids (e.g. water)

qualitative physical property + example

based on the qualities or characteristics of a substance (e.g. colour, clarity, taste, smell)

quantitative physical property + example

measured or expressed by numbers. they provide specific numerical information about a substance (mass, volume, density, boiling/melting point)

compound + example

a pure substance that is made out of two or more elements that are combined together chemically (e.g. CH₄ = methane)

democritus

proposed that matter is made up of small, indivisible particles called “atoms”

john dalton

in the early nineteenth century he classified different atoms based on their relative masses and believed that the atomic model was shaped like a billiard ball (a sphere with mass). he also created the atomic theory of matter stating that:

1. matter is made up of small particles called atoms

2. the atoms of an element are identical to each other

3. the atoms of different elements have different particles

4. atoms join together to form groups of atoms called compounds

j.j. thomson

in the late nineteenth century, experimented with cathode rays. scientists knew that atoms contain small, negatively charged bits called electrons (e-). e- could be easily removed from the atom.

• atoms are neutral so they must contain a positive charge to balance out the negative charge

created the blueberry muffin model which theorized that the electrons were the the blueberries and were surrounded by positive charge (the dough).

thus he concluded that

• negatively charged electrons are stuck inside the positively charge

• the positive charges were call protons

ernest rutherford

created the gold foil experiment which shot a stream of positively charged particles into a sheet of gold foil, in which most particles went straight through the foil while others bounced off.

• proved rthat atoms are mostly empty space except for a dense area in the centre of the atom (the nucleus) which is positively charged

• like charges repel which explains why some positive particles would bounce off the foil if they hit the positively charged nucleus

• electrons can be found anywhere outside of the nucleus in an electron cloud. they are held in by electrostatic forces 9opposite charges attract)

he also discovered that the mass of the nucleus was uch heavier than the mass of the protons, so there must be some particles with no charge in the nucleus.

• discovered that the nucleus of an atom contains protons and neutrons

niehls bohr

did the flame test experiment and noticed that different elements produced different colours when placed in a flame (e.g. iron and magnesium). created the solar system model and concluded that electrons exist in shells or orbits (energy levels) around the nucleus

• when electrons gain energy (heat) they jump from a lower energy shell to a higher energy shell

• when electrons lose energy, they fall back to a lower energy shell releasing light in the form of colour