Example of element
Zinc, oxygen, carbon
Element
A substance made up of only 1 type of atom
Compound
2 or more elements chemically combined
Compound example
Sodium chloride, hydrogen sulfide
Mixtures
2 or more different substances that are NOT chemically combined
Mixture example
Salt water, air
Atom
The smallest particle of a substance that can exist and still be that substance
Nucleus
Found in the centre of atoms, it contains protons and neutrons
Electron
Negative particles surrounding the nucleus
Protons
Positive particles found in the nucleus
Neutrons
Neutral particles found in the nucleus
Sub Atomic Particles
A particle less complex than an atom. Protons electrons and neutrons are all a subatomic particles
Atomic Number
The atomic number is equal to the number of protons in an atom
Mass number
The mass number is equal to the number of protons added onto the number of neutrons in an atom
Isotope
An atom that has the same number of protons but a different number of neutrons. Same atomic number different mass number.
Can be radioactive
Shells
Regions around the nucleus where where electrons travel around the nucleus at high speed
Valence Electrons
an electron in the outer shell of an atom which can combine with other atoms to form molecules
Reactants
The different substances added together to create a chemical reaction
Products
Compounds formed after a chemical reaction has taken place
Law of conservation
The law that states that the mass of the reactants equals the mass of the products
Law of Constant Proportions
The law states that no matter what happens certain elements will always bind with other specific elements
E.g. 2 atoms of Oxygen will always bind with 1 atom of carbon to form CO2
Enthalpy
Stored energy in the bonds that hold atoms together