pure substances

Substances with a definite chemical composition and physical and chemical properties. They are homogenous.

mixtures [ impure substances]

They are made of 2 or more elements, compounds, or both in any proportion. They do not have any definite properties and instead retain the properties of their components. They can be either homogeneous or heterogeneous.

element

It is a pure substance that cannot be converted to anything simpler than itself by any physical or chemical process. They are made of the same types of atoms.

characteristics of elements

1. Simplest type of pure homogeneous substance. 2. Cannot be broken down into simpler substances that exhibit all the properties of that element. 3. They have fixed melting and boiling points. 4. Elements can react chemically with other elements and compounds to form new substances.

metals states

All are solid except for mercury [ liquid ].

non metals states

All are gas or solid except bromine [ liquid ].

metalloids states

all are hard solids

atomicity

the no. of atoms in a molecule of an element.

monoatomic molecules

metals, metalloids, inert gases

polyatomic/ diatomic/ triatomic molecules

non- metals

metal properties

1. lustrous 2. hard solids 3. malleable 4. ductile 5. good conductors of heat and electricity 6. sonorous

exceptions to metal properties

1. sodium and potassium are soft materials. 2. mercury is liquid 3. zinc is brittle 4. tungsten is a poor conductor of electricity

non metal properties

1. no lustre 2. can be soft solids, liquids, or gases 3. neither malleable nor ductile 4. bad conductors of heat and electricity 5. not sonorous

exceptions to non metal properties

1. iodine and graphite are lustrous 2. carbon fiber is ductile 3. graphite is good conductor of electricity 4. diamond is hardest naturally occurring substance

metalloids

have properties of metals and non-metals

noble gases properties

1. not reactive in nature 2. all gases 3. found in traces in air

water

H₂O

ammonia

NH₄

carbon dioxide

CO₂

sodium chloride

NaCl

glucose

C₆H₁₂O₆

sodium bicarbonate/ baking soda

NaHCO₃

sodium carbonate

Na₂CO₃

calcium carbonate/ marble/ chalk

CaCO₃

silicon dioxide/ sand

SiO₂

acetic acid/ vinegar

CH₃COOH

copper sulphate

CuSO₄

magnesium oxide

MgO

potassium hydroxide

KOH

calcium hydroxide

Ca(OH)₂

hydrochloric acid

HCl

nitric acid

HNO₃

sulphuric acid

H₂SO₄

silver nitrate

AgNO₃

barium chloride

BaCl₂

calcium oxide

CaO