Final answer:
X represents the element krypton (Kr), with an atomic number of 36. Without additional context about the number of neutrons, we cannot determine which specific isotope of krypton is represented by the mass numbers given in the options.
Step-by-step explanation:
The element represented by X is krypton (Kr). The subscript 36 in Kr9536, Kr9636, Kr9736, and Kr9836 refers to the atomic number of the element, which is the number of protons in the nucleus and defines the element's identity. According to the periodic table, the atomic number of krypton is 36.
To determine which isotope of krypton is represented by X, we must look at the mass number, which is the sum of protons and neutrons in the nucleus. The options given are 95, 96, 97, and 98, which correspond to the mass numbers in the isotope notation. Since Kr has 36 protons (its atomic number), we subtract this from the mass numbers to find the number of neutrons: 95-36=59, 96-36=60, 97-36=61, and 98-36=62.
There is no additional information provided to select the correct isotope based solely on neutron count. Therefore, without further context or specific information about the number of neutrons present in X, we cannot confidently choose between options A, B, C, or D. They all represent isotopes of krypton but with differing numbers of neutrons.