Matter And Material Part 1

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Definitions

Atom- smallest particle and element can exist

Molecule- consists of 2 or more non-metal atoms

Elements- purest form of a substance that consists of 1 type of atom

Diatomic molecule- Two non- metal atoms chemically combined

Compounds-Two or more different elements that have chemically combined in a fixed ratio

ionic crystal lattice-

When metal atoms chemically combine with non-metal atoms to form Ions. A regular arrangement of positive and negative ions results in a crystal lattice.

Chemical formula- The simplest ratio with which elements combine to form a compound.

Ductile- Metals that can be drawn into thin wire

Malleable- Metals that can be molded into shape or hammered

metal- A solid material that is solid at room temperature (except Hg) and malleable and ductile

non-metal- Are elements that are insulators and they can be gases , liquids or solids

semi-metal- Are elements that have both metallic and non-metallic properties

atomic number- Number of protons in the nucleus of an atom. NOTE the number of electrons equals the number of protons in a neutral atom.

mass number-

Number of protons and neutrons in the nucleus of an atom. Note : to calculate the number of neutrons= atomic mass subtract atomic number

ions- Atoms which have lost or gained electrons.

cation- An atom that has lost electrons forms a cation

anion- An atom which has gained electrons forms an anion

valence electron- An electron found in the outer shell ( energy level) of an atom

valency- The charge number on an element indicating how many electrons have been gained or lost

exothermic reaction-

During a chemical reaction more energy is given out to form product bonds than is taken in to break Reactant bonds. Eg usually you will see light or heat energy in the form of an explosion and the measured temperature increases

endothermic reaction- During a chemical reaction more energy is absorbed to break reactant bonds that is given out to form

Product bonds. Eg temperature of the reaction usually decreases

mixture- A mixture is a combination of two or more elements or compounds that can be separated using a physical technique.

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DIFFERENCE BETWEEN ELEMENTS AND COMPOUNDS

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