Radioactive isotope used in dating ancient objects is:
A. Carbon-14
B. Cobalt-60
C. Iodine-131
D. Uranium-235
Answer: Option A
Solution (By JKExamLibrary)
Carbon-14 dating is used to determine age of organic materials up to ~50,000 years based on its half-life of 5730 years. Cobalt-60 for cancer therapy, iodine-131 for thyroid, uranium-235 for nuclear fuel.
Explanation:
Sodium has the electronic configuration [Ne]3s1. After losing one electron to form Na+, it achieves a highly stable noble gas configuration ([Ne]). Removing a second electron from this stable core requires an exceptionally large amount of energy. Thus, sodium has the highest second ionization energy among these elements.
Explanation:
Graham's law of effusion/diffusion applies to gases. It states that rate is inversely proportional to square root of molar mass. It is used to separate isotopes.
Explanation:
Carbon has 4 valence electrons; it forms four covalent bonds by sharing electrons to achieve octet. It does not form ionic bonds easily due to high ionization energy and electron affinity.
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