The bleeding in a subdural hematoma is under the skull and outside the brain, not in the brain itself. As blood accumulates, however, pressure on the brain increases. The pressure on the brain causes a subdural hematoma's symptoms.auses of Subdural Hematoma. Subdural hematoma is usually caused by a head injury, such as from a fall, motor vehicle collision, or an assault. The sudden blow to the head tears blood vessels that run along the surface of the brain. This is referred to as an acute subdural hematoma.
Chemistry Glossary Definition of Ion. An ion is a chemical species that has a greater or lesser number of electrons compared to the number of protons. In other words, it has an electrical charge imbalance.
Best Answer: hi:-) ok, an in chemistry, an ion is formed when an atom of any element either loses or gains one or more electrons. for example, the atomic number for nitrogen, as seen on the periodic table is 7,ie. it has 7 electrons.