Write the electronic configuration of the Na +, Mg2 +, Ca2 + and Rb + ions. Research the size of these ions in picometers and order them in descending order of their size.

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

What is impossible to do with a hypothesis

What is the measured amount of a product obtained from a chemical reaction?