Elements and Compounds
Compounds Chemical equations
Elements are made up of only one type of atom When In Chemical formulae, the little number
two or more atoms bond together we have a written below the symbol indicates the
molecule number of atoms of that element in that
When atoms of two or more elements react & join, compound, e.g., 02.
molecules of a compound are formed.
Compounds have different properties to the elements If there is no number, it indicates that there
they are made up of is only one atom of that element, e.g., C
A single “particle” of a compound is a molecule. If there is a number in front of the
formula, it shows the number of
molecules needed in a reaction, e.g., 2H20
Naming Compounds
How to know if an equation is
If you have 2 elements ina compound – it will have the
ending “ide” Eg: Carbon dioxide = carbon and oxygen,
balanced:
sodium chloride = sodium and chlorine, calcium sulfide In science, matter cannot be destroyed or
= calcium and sulfur, calcium fluoride = calcium and created during a chemical reaction so the
fluorine. number of atoms on the left side of the
If you have 3 elements in a compound – it will have the chemical equation (reactants, which are
ending “ate” Eg: sodium bicarbonate = sodium, carbon needed to make the new molecule) must be
and oxygen, potassium equal to the number of atoms on the right
nitrate = potassium, nitrogen and oxygen, copper side (products, which are made during the
carbonate = copper, carbon and oxygen. reaction.)
Chemical Formula
Every compound has a chemical formula, e.g., water’s
chemical formula is H2O. The chemical formula tells us
all this about the compound:
The name of the compound
What elements are in the compound.
How many atoms of each element there are.
How many atoms are in one molecule of the
compound.
Prefixes in compound names:
Mono = one atom e.g., carbon MONOxide (CO)
Di = Two atoms e.g., carbon DIoxide (CO2) copper,
carbon, and oxygen.
Diatomic elements
Some elements are not made of from single atoms.
Molecule: two or more atoms that are chemically
bonded together.
Diatomic molecule: molecule that consists of exactly
two atoms.
Compounds Chemical equations
Elements are made up of only one type of atom When In Chemical formulae, the little number
two or more atoms bond together we have a written below the symbol indicates the
molecule number of atoms of that element in that
When atoms of two or more elements react & join, compound, e.g., 02.
molecules of a compound are formed.
Compounds have different properties to the elements If there is no number, it indicates that there
they are made up of is only one atom of that element, e.g., C
A single “particle” of a compound is a molecule. If there is a number in front of the
formula, it shows the number of
molecules needed in a reaction, e.g., 2H20
Naming Compounds
How to know if an equation is
If you have 2 elements ina compound – it will have the
ending “ide” Eg: Carbon dioxide = carbon and oxygen,
balanced:
sodium chloride = sodium and chlorine, calcium sulfide In science, matter cannot be destroyed or
= calcium and sulfur, calcium fluoride = calcium and created during a chemical reaction so the
fluorine. number of atoms on the left side of the
If you have 3 elements in a compound – it will have the chemical equation (reactants, which are
ending “ate” Eg: sodium bicarbonate = sodium, carbon needed to make the new molecule) must be
and oxygen, potassium equal to the number of atoms on the right
nitrate = potassium, nitrogen and oxygen, copper side (products, which are made during the
carbonate = copper, carbon and oxygen. reaction.)
Chemical Formula
Every compound has a chemical formula, e.g., water’s
chemical formula is H2O. The chemical formula tells us
all this about the compound:
The name of the compound
What elements are in the compound.
How many atoms of each element there are.
How many atoms are in one molecule of the
compound.
Prefixes in compound names:
Mono = one atom e.g., carbon MONOxide (CO)
Di = Two atoms e.g., carbon DIoxide (CO2) copper,
carbon, and oxygen.
Diatomic elements
Some elements are not made of from single atoms.
Molecule: two or more atoms that are chemically
bonded together.
Diatomic molecule: molecule that consists of exactly
two atoms.
