21. Which statement about one atom of an element identifies the element? A) The atom has 1 proton. B) The atom has 2 neutrons. C) The sum of the number of protons and neutrons in the atom is 3. D) The difference between the number of neutrons and protons in the atom is 1.

What is the ph of a solution with a 1.50 × 10−9 m hydroxide ion concentration?

After watching the video "zinc strip in copper nitrate solution", and reading the instructions, click on the link labeled "start" just below the drawing of the pencil tip. follow the direction to complete the 3x3 grid. answer the below questions for the portion of the activity in which sn(s) is placed in agno3(aq)

Which statement best explains the relationship between an area is geography and the temperature of its surface water