Each atom is made from a nucleus - containing protons and neutrons - which is orbited by electrons.
The atomic number is the number of protons in the atom. The elements in the periodic table are ordered by atomic number.
The atomic mass is the total number of protons and neutrons.
An atom is 1 single thing.
A compound is 2 or more atoms bonded together - the atoms must be different.
A molecule is 2 or more of any atom bonded together - the atoms can be the same
In a atom, the number of protons equals the number of electrons.
1 of 4
Protons, Neutrons and Electrons
At the centre of every atom is a nucleus containing protons and neutrons.
Electrons are contained in shells around the nucleus.
The number of electrons is always the same as the number of protons in the nucleus.
Each proton has an electrical charge of +1
Each electron has an electrical charge of -1
Each neutron has no charge meaning it is neutral.
An atom has the same number of protons as electrons meaning the overall charge is 0 (neutral)
2 of 4
Counting Atoms
The little numbers apply only to the letter before them. eg; CH4 = 1 carbon and 4 hydrogen.
The big numbers apply to the whole of that part of the equation after them. eg; 2H2O = 4 hydrogens and 1 oxygen
The atoms are the amount of each element and the elements are the amount of letters there are.
3 of 4
Balancing Equations
A balanced equation si a symbolic representation showing the kind and amount of the starting materials and products of a reaction. There is the same amount of each element on each side of the equation. eg; 2Na + Cl2= 2NaCl is a balanced equation.
To balance an equation you can only change the big numbers not the little ones. eg; Na + Cl = 2NaCl would become 2Na +2Cl = 2NaCl.
Comments
No comments have yet been made