How does one isotope differ from another?

A toaster has a heating element of 

Which of the following affects the electrical resistance of a wire?

In the United States, the vibrational rate of alternating current is commonly

The smallest particle of an element that has all the element’s chemical properties is a/an

Why are heavier elements much larger than lighter elements?

Which element has the lightest atoms?

An atoms consists mostly of

Why are metals good conductors of both heat and electricity?

The rate of energy transfer is