What does the 195 represent in the isotope notation?
${ }_{78}^{195} Pt$
A. atomic number
B. neutron number
C. atomic mass
Answer (1)
The isotope notation is represented as Z A X , where A is the mass number and Z is the atomic number.
In the given notation 78 195 Pt , 195 is in the position of the mass number ( A ).
Therefore, 195 represents the mass number.
The mass number is ma ss .
Explanation
Understanding Isotope Notation The isotope notation is a symbolic way to represent the composition of an atom's nucleus. In the notation Z A X , where X is the element symbol, A is the mass number, and Z is the atomic number. The mass number ( A ) represents the total number of protons and neutrons in the nucleus, while the atomic number ( Z ) represents the number of protons in the nucleus.
Identifying the Mass Number In the given isotope notation, 78 195 Pt , the number 195 is in the position of A in the general notation. Therefore, 195 represents the mass number of the platinum isotope.
Final Answer Thus, the 195 in the isotope notation 78 195 Pt represents the mass number.
Examples
Isotope notation is used in various fields, such as nuclear chemistry and geology. For example, carbon-14 ( 6 14 C ) dating uses the known decay rate of carbon-14 to estimate the age of organic materials. The mass number 14 indicates that this carbon isotope has 6 protons and 8 neutrons. Similarly, in medical imaging, isotopes like iodine-131 ( 53 131 I ) are used as radioactive tracers. The mass number 131 helps scientists track the isotope's movement within the body, aiding in diagnosis and treatment.
