So sánh hiệu ứng cảm ứng (-I) của các nhóm sau: a. –F , -OH , -NH2
b. –O+R2 , -N+R3 , -F , -Cl , -Br , -I
c. -SOR , -NO2 , -SO2R

An alpha particle is: a hydrogen atom a nucleus of helium two neutrons an electron

The equation below shows a chemical reaction. a + b + heat —> c + d according to the law of conservation of energy, which statement is true? a. the reactants absorb heat because they have less energy than the products. b. the products release heat because they have more energy than the reactants. c. the reactants generate heat because they have more energy than the products. d. the products require heat to form because they have less energy than the reactants.

Why do elements in groups share more chemical properties than elements in a period?