Atoms & Elements

Atoms & Elements

1. proton 1 unit positive (+1) neutron 1 unit neutral electron negligible negative (-1)

   • 32 electrons in the fourth energy level
   • 2 electrons in the first energy level
   • 8 electrons in the second energy level
   • 18 electrons in the third energy level

2. Isotopes are atoms of the same element, with the same number of protons but different numbers of neutrons.

3. An element is a substance that is made up of one kind of atom only.

4. An atom is he smallest particle of a chemical element that can exist.

   • Atoms consist of electrons surrounding a nucleus that contains protons and neutrons.

5. The atoms of any element are different from the atoms of any other element. So iron contains a different sort of atoms from those of sulfur, and the atoms in carbon are different from those of oxygen.