Meningioma; Synonyms: Meningeal tumor: A contrast-enhanced CT scan of the brain, demonstrating the appearance of a meningioma: Specialty: Neurosurgery: Symptoms: None, seizures, dementia, trouble talking, vision problems, one sided weakness: Usual onset: Adults: Types: Grade I, II, III: Risk factors: Ionizing radiation, family history: Diagnostic method
A polar covalent bond shares electrons unequally. Because of this unequal sharing, one end of the molecule is slightly positive, and the other end slightly negative. Edit
In covalent bonds, the electrons are shared, so that each atom gets a filled shell. When the distribution of electrons in molecules is considered in detail, it becomes apparent that the sharing is not always perfectly fair: often, one of the atoms gets more of the shared electrons than the other does.