Which has a larger radius, the oxygen atom (O) or oxygen ion (O-2) ? Explain.
Isn't the ion bigger because negative ions are bigger than atom's radius. im not sure though.
Yes and yes but the reasoning is no very good. The negative ions are larger than their neutral atom because the electrons, all going into the outer shell (which is already occupied with electrons) repel each other and that takes up more space.
The oxygen atom (O) has a larger radius than the oxygen ion (O-2). This is because when an atom gains or loses electrons to become an ion, the electronic configuration changes, causing a change in the effective nuclear charge experienced by the remaining electrons.
In the case of an oxygen atom, it has 8 electrons surrounding its nucleus. When it gains two electrons to become an oxygen ion (O-2), it now has a total of 10 electrons. These additional electrons increase the electron-electron repulsion, causing the electron cloud to expand and the radius to decrease.
Therefore, the oxygen ion (O-2) is smaller in size compared to the oxygen atom (O), contrary to what you mentioned.
To determine which has a larger radius, the oxygen atom (O) or oxygen ion (O-2), we need to understand the concept of atomic and ionic radii.
Atomic radius refers to the distance from the nucleus to the outermost electron shell of an atom. Ionic radius, on the other hand, refers to the distance from the nucleus to the outermost electron shell of an ion.
When an atom gains or loses electrons, it becomes an ion. In the case of oxygen, the oxygen atom (O) has 8 electrons, while the oxygen ion (O-2) has gained 2 electrons, resulting in a total of 10 electrons.
The general trend for atomic and ionic radii is that they increase as you move down a group on the periodic table and decrease as you move across a period. This trend is influenced by factors such as effective nuclear charge and shielding effect.
In the case of oxygen, it belongs to Group 16 (also known as Group VIA) of the periodic table. Oxygen is located in the second period of the table. As you move down Group 16, the atomic radius generally increases due to the addition of more electron shells.
Now, let's compare the oxygen atom (O) to the oxygen ion (O-2). Since the oxygen ion has gained 2 electrons compared to the oxygen atom, it has a greater number of electrons. The additional electrons increase the electron-electron repulsion, causing the outermost electron shell to expand.
Based on this information, we can infer that the oxygen ion (O-2) has a larger radius than the oxygen atom (O). Therefore, your initial assumption that the ion is bigger is correct.
Remember, to determine relative atomic and ionic radii, it is helpful to consider the position of the element on the periodic table and the number of electrons gained or lost by the atom or ion.