What does it mean if a solution is a "weak acid "? Strong acid? Give logical ph values for each

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.

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons

What did the experiments of scientists after john dalton reveal about his atomic theory?