rank the following atoms and ions in the order of expected increasing radius: Ca, Ca2+, Ar
Pls pls help me kindly... Anyone?
Ca+2<Ar<Ca
by amar chauhan
right!!!
first chop some carrots and then eat some grass. :)
Of course! I'd be happy to help you with that.
To rank the atoms and ions in order of expected increasing radius, you need to consider their respective electron configurations and the effective nuclear charge.
Let's start by looking at the electron configurations:
- Calcium (Ca): The atomic number of calcium is 20, so it has 20 electrons. The electron configuration of calcium is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².
- Calcium ion (Ca²⁺): The calcium ion has lost two electrons, so it has 18 electrons. The electron configuration of the calcium ion is 1s² 2s² 2p⁶ 3s² 3p⁶.
- Argon (Ar): Argon is a noble gas and has a completely filled electron configuration. It has 18 electrons arranged as 1s² 2s² 2p⁶ 3s² 3p⁶.
Now, let's consider the effective nuclear charge. The effective nuclear charge is the net positive charge experienced by the valence electrons and affects the size of the atom or ion. As you move across a period, the effective nuclear charge increases, leading to a smaller atomic radius.
Based on these facts, we can rank the atoms and ions in order of expected increasing radius:
1. Ca²⁺ (smallest) - The effective nuclear charge is highest since it has lost two electrons and the remaining electrons experience a higher attraction to the nucleus.
2. Ca - Although calcium loses two electrons to become a cation, it still has more electrons compared to the calcium ion (Ca²⁺), resulting in a larger radius.
3. Ar (largest) - Argon has a completely filled electron configuration, making it the largest among the three species.
So, the correct order of increasing radius is: Ca²⁺ < Ca < Ar.