A pictorial periodic table of elements
All the atoms that make up a single element have the same number of protons.
All atoms except those of the simplest form of hydrogen also contain neutrons.
Electrons circle the nucleus at different distances depending on how much energy they have.
- The basic chemicals of the Universe are elements – material produced by or used in a reaction involving changes in atoms, and they cannot be broken down into other substances – solid mass.
- elements are formed entirely of atoms that contain the same number of protons in their nuclei – for example: all hydrogen atoms have one proton.
- more than 100 elements are known.
- simplest and lightest elements; Â hydrogen and helium – formed nearly 14 billion years ago in the history of the Universe. (See Big Bang)
- other elements formed; nuclei of the atoms of the light elements joined by nuclear fusion.
- nuclear fusion of element atoms – happens deep inside the stars at the end of their lives.
- lighter elements; such as oxygen and carbon – the first to form.
- helium nuclei fuse with oxygen and neon atoms to form atoms; such as silicon, magnesium and calcium.
- heavy atoms form – when supergiant stars reach the end of their life and collapse – boosting the pressure of the gravity in their core.