Cho hai điện tích q1 = 2. 10-6 C, q2 = 4. 10-6 C, đặt tại A và B trong không khí biết AB = 2 cm. Xác định vectơ cường độ điện trường tại: a) H, là trung điểm của AB.
b) . M, MA = 1 cm, MB = 3 cm.
c) N, biết rằng NAB là một tam giác đều.

Use examples from the article to explain one positive and one negative effect that chemistry has had on society.

The table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

Which sentence about particles in matter is true? a. atoms are present in solids and liquids but not in gases. b. the particles of matter are in constant motion. c. the same kinds of atoms are found in different elements. d. when a solid changes to a liquid, the sizes of the particles change.