How is the number of neutrons in an average atom determined?
The number of neutrons in an average atom is determined by the mass number (M) and the atomic number (Z) of the atom. The mass number is the total number of protons and neutrons in the nucleus of an atom, while the atomic number is the number of protons in the nucleus. The number of neutrons can be calculated by subtracting the atomic number from the mass number. In a neutral atom, the number of neutrons is equal to the number of protons.
Mass Number and Atomic Number
The mass number (M) of an atom is the sum of its protons and neutrons. It is represented as a superscript on the left side of the atomic symbol. For example, in Nitrogen-14, the mass number is 14.
The atomic number (Z) of an atom is the number of protons in its nucleus. It is represented as a subscript on the left side of the atomic symbol. For Nitrogen-14, the atomic number is 7.
Calculating the Number of Neutrons
To calculate the number of neutrons in an atom, you simply subtract the atomic number from the mass number. In the case of Nitrogen-14:
Number of neutrons = Mass number - Atomic number
Number of neutrons = 14 - 7
Number of neutrons = 7
Therefore, in an average Nitrogen-14 atom, the number of neutrons is 7.
Summary: The number of neutrons in an atom is determined by the mass number and the atomic number. By subtracting the atomic number from the mass number, you can calculate the number of neutrons present in an average atom. In the case of Nitrogen-14, with a mass number of 14 and an atomic number of 7, the number of neutrons is 7.