Select all the correct answers.
The electron configurations of some elements are given. Based on the electron configurations, which elements can likely form ions with multiple charges?
zinc $[ Ar ] 3 d^{10} 4 s^2$
Iron $[ Ar ] 3 d^6 4 s^2$
sodium [ Ne ] $3 s^1$
cobalt $[A r] 3 d^7 4 s^2$
silver $[ Kr ] 4 d^{10} 5 s^1$
Answer (2)
Iron (Fe) has a partially filled d orbital ( 3 d 6 ) and can form F e 2 + and F e 3 + ions.
Cobalt (Co) has a partially filled d orbital ( 3 d 7 ) and can form C o 2 + and C o 3 + ions.
Silver (Ag) has a filled d orbital ( 4 d 10 ) and one s electron ( 5 s 1 ), and can form A g + and A g 2 + ions.
Therefore, the elements that can form ions with multiple charges are Iron, Cobalt, and Silver.
Explanation
Problem Analysis We are asked to identify elements that can form ions with multiple charges based on their electron configurations. Transition metals, which have partially filled d orbitals, are known for exhibiting variable valency and forming ions with multiple charges. Let's analyze the given electron configurations to determine which elements fit this criterion.
Zinc Analysis Zinc (Zn): [ A r ] 3 d 10 4 s 2 . Zinc has a completely filled d orbital. It typically loses the two 4s electrons to form Z n 2 + . It does not readily form other ions.
Iron Analysis Iron (Fe): [ A r ] 3 d 6 4 s 2 . Iron has a partially filled d orbital. It can lose two 4s electrons to form F e 2 + , and it can also lose an additional d electron to form F e 3 + . Therefore, iron can form multiple ions.
Sodium Analysis Sodium (Na): [ N e ] 3 s 1 . Sodium has only one valence electron. It readily loses this electron to form N a + . It does not typically form other ions.
Cobalt Analysis Cobalt (Co): [ A r ] 3 d 7 4 s 2 . Cobalt has a partially filled d orbital. It can lose two 4s electrons to form C o 2 + , and it can also lose an additional d electron to form C o 3 + . Therefore, cobalt can form multiple ions.
Silver Analysis Silver (Ag): [ Kr ] 4 d 10 5 s 1 . Silver has a completely filled d orbital and one s electron. It commonly loses the s electron to form A g + . It can also lose a d electron to form A g 2 + , although A g + is more common. Therefore, silver can form multiple ions.
Conclusion Based on the analysis, iron, cobalt, and silver can form multiple ions.
Examples
Understanding which elements can form multiple ions is crucial in various applications, such as designing catalysts, creating alloys with specific properties, and developing new chemical compounds. For example, iron's ability to form both F e 2 + and F e 3 + ions makes it an essential component in many biological systems, including hemoglobin, which carries oxygen in the blood. Similarly, the variable valency of cobalt is utilized in vitamin B12, which plays a vital role in cell growth and DNA synthesis. Silver's ability to form A g + ions makes it useful in antimicrobial applications.
Iron, Cobalt, and Silver can likely form ions with multiple charges due to their partially filled d orbitals, which allow them to lose different numbers of electrons. Zinc and Sodium do not typically form ions with multiple charges, as they have filled or nearly filled orbitals. Therefore, the correct choices are Iron, Cobalt, and Silver.
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