Question

What happens to the atomic radius of an element when it loses an electron? Why?

Answer 1

When an element loses an electron, its atomic radius typically decreases.

The atomic radius is defined as the distance from the nucleus of an atom to the outermost electron shell. When an atom loses an electron, it loses an outer electron from its electron cloud. As a result, there is a reduced electron-electron repulsion (because there are fewer electrons) and a stronger effective nuclear charge (the positive charge of the nucleus experienced by the remaining electrons).

This stronger effective nuclear charge pulls the remaining electrons closer to the nucleus, reducing the atomic radius. The loss of an electron results in a higher positive charge in the nucleus compared to the number of electrons, causing the remaining electrons to be more strongly attracted to the nucleus, hence decreasing the atomic radius.

Simpler explanation:

Imagine an atom like a tiny planet with smaller particles called electrons flying around it. The size of this "planet" (the atom) is called the atomic radius. When this atom loses an electron, it's like it's losing a small friend flying around it.

Now, when it loses this electron friend, the other electrons left behind feel a stronger pull from the center (the nucleus) because there are fewer "friends" flying around. Just like when there are fewer friends playing tug-of-war, it's easier for the other side to pull the rope.

So, when an atom loses an electron, the pull from the center gets stronger, and the atom becomes a bit smaller because the remaining electrons are pulled closer to the center.

Answer 2

When an element loses an electron to form a cation, the atomic radius of the element decreases. This occurs because the loss of an electron reduces the electron-electron repulsion, causing the remaining electrons to be drawn closer to the nucleus.

The atomic radius of an atom is defined as half the distance between the nuclei of two atoms of the same element that are joined by a single covalent bond. When an electron is lost, the electron-electron repulsion decreases, and the attraction between the remaining electrons and the nucleus becomes stronger. As a result, the remaining electrons are pulled closer to the nucleus, reducing the atomic radius.

In summary, when an element loses an electron to form a cation, the atomic radius decreases due to the increased nuclear charge and the reduced electron-electron repulsion.