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.
the largest is francium, Z=87 , or caesium, Z=55 ; and the smallest is definitely helium, Z=2 .
Explanation:
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D.) There must be an equal number of atoms of each element on both sides of the equation
D = m / V
0.736 = 225.0 / V
V = 225.0 / 0.736
V = 305.7 cm³
