Basic Chemistry

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Fiona Headley
Basic chemistry
Matter is anything that has mass and takes up space.
There are two types of properties of substances; chemical and physical.
Physical properties are properties that can be observed without changing the identity of
the substance, so basically it is the same thing in a different state. For example when ice
is melted.
Chemical properties are only observed when a chemical changes identity, for example
during a chemical reaction.
An element is a substance that cannot be broken down into 2 or more different
substances.
An atom is the smallest, uncharged particle of an element.
A compound is two or more elements chemically joined together.
Elements are formed by nuclear fusion in stars.
There are 112 elements that have been discovered. 90 of these occur naturally on Earth.
The Periodic Table
Dmitri Mendeleev organised the elements in order of atomic number to produce the
periodic table.
The vertical columns on a periodic table are called groups.
The horizontal rows on a periodic table are called periods.
Elements in the same group have similar chemical properties.
M1, Core Principles of Chemistry

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Fiona Headley
Elements in the same period have the same number of electron shells surrounding the
nucleus.
Metals are on the left and middle of the periodic table, non-metals are on the right.
Metalloids are semi-metals found on the border between the metals and non-metals on
the periodic table.…read more

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Fiona Headley
Properties of metals, non-metals
and metalloids
Physical properties of metals:
o Conduct electricity when solid or liquid
o Malleable and ductile
o Solid at room temperature except for mercury
Chemical properties of metals:
o Form cations
o Metal + acid salt + hydrogen
o Metal + water hydroxide + hydrogen
o Displacement reactions; more reactive metals displace less reactive ones
o Metals are more reactive as you go down the groups
o Metal oxides and hydroxides are bases
Chemical properties of non-metals:
o…read more

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Fiona Headley
Forces and energy
There are four types of forces; strong nuclear, weak nuclear, gravitational and
electromagnetic.
An ion is a charged atom or group of atoms.
Cations are positive ions that are formed when an element loses electrons.
Anions are negative ions that are formed when an element gains electrons.
Opposite charges of ions attract, similar charges repel.
Energy is needed to separate particles that are attracted to each other and is given off
when 2 opposite charges get closer to each other.…read more

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Fiona Headley
Measurements
Mass is usually measured in grams (g).
Volume is usually measured in cm3.
A mole (mol) is the number of carbon atoms in exactly 12g of 12C.
The Avogadro constant is the number of particles in a mole; 6.02 x 1023
Chemicals react in mole ratios.
Answers in chemistry need to be rounded to the appropriate number of significant
figures, which is usually 3s.f.…read more

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