What is the density of an object, and what is an example of density?

Which of the following pairs of elements belong to the same groupa. h and he b. li and bec. c and pb d. ga and ge

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)

Compare and contrast the bohr model and the electron cloud models of the atom.