Which of the following is true about ions

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.

Write the chemical formula for a compound that is made of an element from group 1 and an element from group 17

How will the volume of a gas be affected if the pressure is tripled, but the temperature remains the same?