Answer:
A
Explanation:
The mass number (represented by the letter A) is defined as the total number of protons and neutrons in an atom. Consider the table below, which shows data from the first six elements of the periodic table. Consider the element helium. Its atomic number is 2, so it has two protons in its nucleus.
<span>d)Electrons need specific amounts of energy to "jump" off an atom and be emitted.</span>
Cooper is the substance that can't be decomposed by a chemical chAnge. So 4)
This is late but for anyone else who needs it...It's D. Far left