What do the nuclei of 1H hydrogen atoms contain? protons only
electrons and protons
electrons and neutrons
neutrons only

A100-watt light bulb radiates energy at a rate of 100 j/s. (the watt, a unit of power or energy over time, is defined as 1 j/s.) if all of the light emitted has a wavelength of 525 nm , how many photons are emitted per second?

What layer of the atmosphere is directly above the troposphere?

An atom of sodium-23 (atomic number = 11) has a positive charge of +1. give this information, how many electrons does it have? how many proteins and neutrons does this atom have