3. look at the positions of calcium, beryllium, and magnesium on the periodic table. based on their locations, predict how many valence electrons these elements have and predict what the reactivity of these elements will generally be.

Write skeleton equations for the following reactions c. aluminum(s)+copper(i) chloride(aq) > aluminum chloride(aq)+copper(s)

Two friends at different locations want to communicate with each other by sending low energy signals. which of the following methods can they use to communicate? a) produce x-rays using colliding electrons and send them to radios, which capture sound b) send messages using infrared radiation, which travel in the form of waves c) send radio waves through intervening media like radio and television d) produce sound waves using microwaves from heated objects

Compare and contrast physical changes with chemical changes.