# Question #17d55

May 21, 2017

The answer is (c) ${\text{H}}^{+}$.

#### Explanation:

An alpha particle consists of $2$ protons and $2$ neutrons, so you can't really say that it contains any electrons.

In fact, an alpha particle is simply the nucleus of a helium-4 atom.

Because alpha particles do not contain any electrons, you must identify which of the chemical species given as options do not contain any electrons.

Right from the start, the hydrogen ion, ${\text{H}}^{+}$, should stand out as the ideal candidate.

As you know, a neutral hydrogen atom contains $1$ proton inside its nucleus and $1$ electrons surrounding the nucleus.

When the hydrogen atom loses its electron, the hydrogen ion is formed. You can thus say that the hydrogen ion contains the same number of electrons as an alpha particle, i.e. $0$ electrons.

That said, it's worth noting that alpha particles contain the same number of protons as a $\text{He}$, i.e. $2$ protons. Moreover, the fact that alpha particles do not contain any electrons implies that they have an overall $2 +$ charge.

$\text{2 protons and 0 electrons " implies " 2+ charge}$