Question

question 1-24
the position of an element on the periodic table helps scientists predict the number of electrons an atom will gain or lose during ion formation. according to the periodic table of the elements, which element is most likely to gain two electrons when it forms an ion?
○ calcium (ca)
○ mercury (hg)
○ oxygen (o)
○ iodine (i)

Explanation:

To determine which element gains two electrons, we analyze each option:

• Calcium (Ca) is in Group 2, so it loses 2 electrons to form a cation.
• Mercury (Hg) is a transition metal; its electron loss/gain is more complex, but it's not typical to gain 2 electrons.
• Iodine (I) is in Group 17, so it gains 1 electron to achieve a stable octet.
• Oxygen (O) is in Group 16. Group 16 elements have 6 valence electrons, so they gain 2 electrons to complete their octet (8 valence electrons) and form an anion (e.g., \(O^{2-}\)).

Answer:

B. oxygen (O)