Elements

• What is an element?


  A substance made up of atoms that all have the same number of protons in their nucleus
• Atoms can have different numbers of proton, neutrons and electron. It’s the number of protons in the nucleus that decides what type of atom it is.
• What is the atom with one proton in its nucleus?


  Hydrogen
• If a substance only contains atoms with the same number of protons it‘s called an element.
• How many different types of elemen are there?

  118 elements
• All atoms of a particular element, no matter the charge, have the same number of protons.
• How can elements be presented in an easier way?


  A one or two letter symbol
• What is an isotope?


  An isotope is a variant of an element that has the same number of protons but a different number of neutrons in its nucleus.
• Isotopes have the same atomic number but different mass numbers.
• How can you work out the number of neutrons?


  Subtract the atomic number from the atomic mass.
• Relative atomic mass is used instead of mass number when referring to the the element as a whole, as elements can exist as a number of different isotopes.
• What is relative atomic mass?


  The average mass of an element taking into account the different masses and abundances (amounts) of all the isotopes that make up the element.
• What is the formula for relative atomic mass?


  Sum of the masses of all the isotopes of an element, multiplied by their relative abundance, divided by the sum of the relative abundances.