If you have allergies, pregnancy can make your symptoms worse. But you're right to worry about taking allergy medicine during pregnancy. Pregnant women shouldn't take some allergy drugs. Certain antihistamines, however, are safe.
free radical. (chemistry). An atom or a diatomic or polyatomic molecule which possesses one unpaired electron. Also known as a radical.ree radical. in chemistry, a molecule or atom that contains an unpaired electron but is neither positively nor negatively charged. Free radicals are usually highly reactive and unstable.
Quantum Chemistry. a branch of theoretical chemistry that considers problems of structure and reactivity of chemical compounds as well as problems of bonding from the point of view of the concepts and methods of quantum mechanics.n principle, quantum mechanics permits calculation of the properties of atomic and molecular systems on the basis of the Schroedinger schrÃ¶dinger, Equation pauli exclusion, principle and universal physical. constants