chemistry - atoms, elements and compounds

atom

the smallest particle of an element that still has the properties of that element

element

a substance containing only one type of atom

compound

a substance that contains at least two different types of compound chemically bonded together

molecule

two or more atoms bonded together

mixture

a substance made up of two or more elements or compounds not chemically bonded together

nucleus

the central part of an atom containing protons and neutrons

proton

a sub-atomic particle with a positive charge

neutron

a sub-atomic particle with no charge

electron

a sub-atomic particle with negative charge

atomic number

number of protons in an atom

mass number

the number of protons + neutrons in an atom

structure of an atom

central nucleus containing neutrons and protons, surrounded by electrons in shells

relative mass and charge of proton

mass: 1, charge: 1+ (positive)

relative mass and charge of neutron

mass: 1, charge: 0 (neutral)

relative mass and charge of electron

mass: 1/1640, charge: 1- (negative)

isotopes

atoms of the same element which have the same proton number but a different nucleon (neutron) number

number of neutrons

mass - atomic no. because most mass of atom is concentrated in the nucleus

relative atomic mass in terms of isotopes

((number of atoms x mass) + (number of atoms x mass))/total number of atoms