which has the largest radius K, Ca, K+ or Na?
To determine which element has the largest radius among K, Ca, K+, and Na, we need to consider their atomic structure. The atomic radius generally decreases as we move from left to right across a period in the periodic table and increases as we move down a group.
K (Potassium) and Na (Sodium) are both in Group 1 (alkali metals), while Ca (Calcium) is in Group 2 (alkaline earth metals). K+ is the ion formed by Potassium when it loses one electron.
Let's compare the atomic structures and sizes of these elements to determine which one has the largest radius:
1. Potassium (K): Atomic number 19, electronic configuration [2, 8, 8, 1].
K has one valence electron in the 4th energy level.
2. Sodium (Na): Atomic number 11, electronic configuration [2, 8, 1].
Na has one valence electron in the 3rd energy level.
3. Calcium (Ca): Atomic number 20, electronic configuration [2, 8, 8, 2].
Ca has two valence electrons in the 4th energy level.
4. Potassium ion (K+):
K+ is formed when Potassium loses one electron.
As a result, the electronic configuration becomes [2, 8, 8], which is the same as that of Argon (Ar).
From the above comparisons, we can conclude that Ca has the largest radius among the given elements. This is because calcium has more energy levels and more electrons than K, Na, and K+.
Therefore, the order of increasing atomic radius is as follows:
K+ < Na < K < Ca