- Define the atomic number as the number of protons (\(Z=P\)) and the mass number as the sum of protons and neutrons (\(M=P+N\)).
- For the first atom: \(A = P = 20\), \(B = P + N = 20 + 20 = 40\), and symbol \(C = \text{Ca}\).
- For the second atom: \(E = P = 9\), \(D = M - P = 19 - 9 = 10\), and symbol \(F = \text{F}\).
- Final answers are \(A = \boxed{20}\), \(B = \boxed{40}\), \(C = \boxed{\text{Ca}}\), \(D = \boxed{10}\), \(E = \boxed{9}\).
Explanation
- Basic Atomic Concepts and Given Data
To determine the properties of the given atoms, we use the fundamental definitions of atomic structure:
- The Atomic Number (\(Z\)) of an element is exactly equal to the number of protons (\(P\)) in its nucleus.
- The Mass Number (\(M\)) is the sum of the number of protons and neutrons (\(N\)) in the nucleus: \(M = P + N\).
We are given two atoms with specific properties to determine:
- For the first atom: Protons = \(20\), Neutrons = \(20\).
- For the second atom: Protons = \(9\), Mass Number = \(19\).
- Analysis of the First Atom
For the first atom, we have \(P=20\) and \(N=20\):
- The Atomic Number \(A\) is equal to the number of protons, so \(A = P = 20\).
- The Mass Number \(B\) is the sum of protons and neutrons, so \(B = P + N = 20 + 20 = 40\).
- The element \(C\) with atomic number \(20\) is Calcium, which has the symbol \(\text{Ca}\).
- Analysis of the Second Atom
For the second atom, we have \(P=9\) and \(M=19\):
- The Atomic Number \(E\) is equal to the number of protons, so \(E = P = 9\).
- The number of neutrons \(D\) is the difference between the mass number and the number of protons, so \(D = M - P = 19 - 9 = 10\).
- The element \(F\) with atomic number \(9\) is Fluorine, which has the symbol \(\text{F}\).
- Final Values
Based on our calculations:
- \(A = 20\)
- \(B = 40\)
- \(C = \text{Ca}\)
- \(D = 10\)
- \(E = 9\)
The completed values are \(A = \boxed{20}\), \(B = \boxed{40}\), \(C = \boxed{\text{Ca}}\), \(D = \boxed{10}\), and \(E = \boxed{9}\).
Examples
Understanding the relationship between protons, neutrons, and the periodic table is vital in fields like nuclear medicine and archaeology. For example, radioactive dating often involves counting the neutrons in isotopes (atoms with the same number of protons but different numbers of neutrons) to determine the age of artifacts. By knowing the atomic number and mass number, scientists can identify the exact isotope and use its known decay rate to calculate its age, effectively using chemistry to reconstruct history.