Naturally occurring hydrogen consists of three isotopes, hydrogen-1 (1.01 u),
hydrogen-2 (2.02 u) and hydrogen-3 (3.01 u), where the isotopic masses are given in parentheses. use the periodic table and determine which isotope is present in the larger percentage in the natural element.
a. hydrogen-1
b. hydrogen-2
c. hydrogen-3
d. each is present at equal percentages.

Hydrogen-1

Explanation:

Not sure what kind of explanation is needed for your question, because it doesnt specify.

The easiest should be:

Average mass of an element is calculated as the sum of the multiplication of each isotope by its percentage

And the mass of the hydrogen is 1, therefore the more abundant is hydrogen-1

answer: the rate of diffusion increases with increase in temperature.

increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.

generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.