Which principal energy level can hold a maximum of 18 electrons?

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

Free answer. the treaty of versailles ended world war i, but some of the terms of the treaty contributed to the beginning of world war ii. which was one of the terms of the treaty? the answer would be "germany was forces to pay reparations to the allied countries.". i hope this .

When a nucleus absorbs a neutron and then breaks apart, there are many products of the reaction. what is not a product of a nuclear fission reaction