How many atoms of carbon are in 2.50 moles of CO2?

Which element has the highest first ionization energy?

Which ion has the largest radius?

How many photons are contained in a burst of yellow light (589 nm) from a sodium lamp that contains 616 kJ of energy?

Which of the following elements is a transition metal?

Choose the pure substance from the list below.

How many valence electrons do alkali earth metals possess?

Identify the color that has a wavelength of 480 nm.

An atom of 17O contains ________ protons.

All samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements. Which law does this refer to?