Answer:
Option D. Activation energy
Explanation:
Activation energy is the minimum energy required to start a chemical reaction. For a reaction to occur, the reactants must possess energy equal or greater than the activation energy else the reaction will not occur.
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Isotopes are forms of the same elements which contain equal number of protons but different number of nucleus in their nuclei, thus the differ in relative atomic mass but they have same chemical properties. The mass number is the summation of number of proton and number of neutron of an atom. If the mass number is known, then one need to know the number of proton in the atom in order to calculate for the number of neutron.
Answer:
Matter is the term for any type of material. Matter is anything that has mass and takes up space. At a minimum, matter requires at least one subatomic particle, although most matter consists of atoms.
Some examples are: Water, books, pencils, sun, earth, moon, electron, proton, mesons, and quarks
