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
The type of bond an atom forms is relative to the behavior of their valence electrons and electronegativity values. The difference in electronegativity between atoms determines if they form a covalent bond or a ionic bond. In an ionic bond, one atom donates its valence electrons to another atom. The electron donor becomes positively charged, and the electron receiver becomes negatively charged. These charged particles become attracted to each other and bond to become stable and neutralize their charges. In a covalent bond, atoms share valence electrons. This allows the atoms to stabilize their inherent charges and become unreactive. Atoms that belong to the noble gas group of elements are generally unreactive and do not form chemical bonds because their valence electron shells are completely full and balanced.