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Atomic Number and Mass Formulas:
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The atomic number (Z) represents the number of protons in an atom's nucleus and determines the chemical element. The atomic mass (A) is the total number of protons and neutrons in the nucleus, measured in atomic mass units (u).
The calculator uses fundamental atomic formulas:
Where:
Explanation: The atomic number defines the element's identity, while atomic mass determines the specific isotope of that element.
Details: Understanding atomic number and mass is fundamental to chemistry and physics. The atomic number determines an element's position in the periodic table and its chemical properties, while atomic mass affects physical properties and isotopic behavior.
Tips: Enter the number of protons and neutrons as whole numbers. Protons must be at least 1, neutrons can be zero or positive. The calculator will compute both atomic number and atomic mass.
Q1: What is the difference between atomic number and atomic mass?
A: Atomic number (Z) counts only protons and defines the element. Atomic mass (A) counts both protons and neutrons and identifies specific isotopes.
Q2: Why don't electrons affect atomic mass?
A: Electrons have negligible mass compared to protons and neutrons (about 1/1836 the mass), so they are not included in atomic mass calculations.
Q3: What are typical atomic number ranges?
A: Naturally occurring elements range from Z=1 (hydrogen) to Z=94 (plutonium), with synthetic elements extending beyond Z=118.
Q4: How does atomic mass relate to atomic weight?
A: Atomic mass refers to a specific isotope, while atomic weight is the weighted average of all naturally occurring isotopes of an element.
Q5: Can two different elements have the same atomic mass?
A: Yes, this is called isobars - different elements with the same atomic mass number but different atomic numbers.