Download Chemistry Exam Review

SNC1D: CHEMISTRY
Atoms, Elements and
Compounds
Exam Review
Mixture
• a substance made of different pure substances
Heterogenous
• not uniform
Homogenous
• uniform (in composition and properties)
Ex. a solution
Pure Substance
• a substance made of only one kind of particle
Element
• a pure substance made of only one kind of atom
Compound
• a pure substance made of more than one type of
atom that have been chemically bonded together
Particle Theory of Matter
1. All matter is made of tiny particles.
2. Different pure substances are made up of different
types of particles.
3. Particles are always in constant random motion.
4. The particles in a substance attract each other.
5. The particles of a substance move faster when
heated.
Physical change
• a change in which no new substances are produced
Ex: ice melting
Chemical Change
• a change in which new substances are produced
Ex: iron rusting
Physical Property
• description of the nature of a substance
Ex: gold is a relatively soft metal
Chemical Property
• description of how a substance reacts with other
substances
Ex: iron rusts
Element Symbols
•
•
•
•
Ca
Cl
Mg
Na
calcium
chlorine
magnesium
sodium
Element Names
•
•
•
•
Oxygen
Iron
Argon
Tungsten
O
Fe
Ar
W
Chemical families
IA
alkali metals
IIA
alkaline earth metals
VIIA
halogens
VIIIA
noble gases
Metals
•
•
•
•
Shiny
Malleable
Good conductors
Found on the left side of the Periodic Table
(most reactive: Alkali Metals)
Non-Metals
•
•
•
•
Dull
Brittle
Poor conductors
Found on the right side of the Periodic Table
(most reactive: Halogen; least: Noble Gases)
Atomic Number
• the number of protons in the nucleus
Atomic Mass
• the number of protons + neutrons in the nucleus
Isotope
• an atom with a different number of neutrons and
therefore a different mass
Experiments
• Thomson’s cathode ray experiments: atoms contain
electrons
• Rutherford’s gold foil scattering experiments: atoms
contain small, dense, positively-charged nuclei
• Bohr’s flame tests: electrons are only found in certain
orbits (energy levels)
Atomic Numbers
Bohr Diagram
Magnesium:
Rows and Columns
• Elements in the 3rd period (row) all have 3 orbits
around the nucleus.
• Elements in the 1st column all have 1 electron in their
outer (valence) orbit.
Word Equations
sulphur + oxygen →
reactants
sulphur dioxide
product
Word Equations
sodium hydroxide reacts with hydrochloric acid to
produce sodium chloride and water
Word Equations
Silver chloride and calcium nitrate are produced when
calcium chloride reacts with silver nitrate.
Valence Shell
• An atom wants 8 electrons in its outer (valence) shell
to be stable.
Valence Shell
How many electrons do elements in the following
families gain or lose to become stable?
i) IA
ii) IIA
iii) VIIA
iv) VIIIA
lose 1
lose 2
gain 1
neither lose nor gain
Ionic Compound
• In an ionic compound, a
positive metal ion is
electrically attracted to a
negative non-metal ion.
Molecular Compound
• In a molecular compound,
non-metals share
electrons.
Covalent Bonding
This sharing is a covalent
bond.
Ionic Compound
NaCl must be an ionic
compound because it
contains a metal.
Methane