What are the extensive properties of carbon

Scuba divers use tanks of compressed air to them breathe. gases can be compressed because?

Which of the following observations indicates that an atom has neutrons? some uncharged particles are scattered by a beryllium atom when it hits a gold foil. some uncharged particles bounce back from a gold foil when it is bombarded with alpha particles. a radiation consisting of uncharged particles is emitted when alpha particles strike beryllium atoms. a radiation which attracts electrons is produced when a beryllium atom is bombarded with alpha particles.

Comparing john newland’s octaves with the modern periodic table, which 5 elements have been discovered between hydrogen and iron since newland’s time?