Answer:
* is a soft,silvery metal that reacts violently with water
Dinitrogen pentachloride has covalent bonds
By 'waves' do you mean sound waves? If so sound waves need to travel through things like solids, liquids and yup <u>gases. </u>When the waves travel they are vibrating the molecules in the matter. By doing this he molecules in solids are packed very tightly.
The two elements that produce background radiation on earth are Radon and Uranium. Airborne radon can decay on its own. Radon undergoes alpha decay to produce Polonium. Uranium naturally undergoes alpha decay to produce Thorium.