Question

Which of the following elements doesn't lie on the same period?

• A. Osmium
• B. Iridium
• C. Palladium
• D. Platinum

Hint:

When determining the period of an element, refer to its atomic number. Elements in the same period have consecutive atomic numbers, with their positions on the periodic table reflecting this.

Answer 1

The Correct Option is C

Let's examine the atomic numbers and periods of the elements: - Osmium (Os) has atomic number 76 and is in Period 6. - Iridium (Ir) has atomic number 77 and is in Period 6. - Palladium (Pd) has atomic number 46 and is in Period 5. - Platinum (Pt) has atomic number 78 and is in Period 6. From the above, we see that Palladium (Pd) does not lie in Period 6, unlike the other elements (Os, Ir, and Pt), which are all in Period 6. Thus, the correct answer is Palladium (Pd).