Question

For the atom \(^{108}\) Pd with mass 107.90389 u, determine (a) the numbers of protons, neutrons, and electrons in the atom; (b) the ratio of the mass of this atom to that of an atom of \(^{12}_{6} \mathrm{H}\)

Short answer

The atom \(^{108}\)Pd has 46 protons, 46 electrons and 62 neutrons. The ratio of its mass to that of \(^{12}_{6}\mathrm{H}\) is approximately \( \frac{107.90389}{12} = 8.99 \)

Step-by-step solution

Determine the Number of Protons and Electrons

The atomic number of Pd (Palladium) is 46 which is also the number of protons in the atom. Because the atom is neutral, the number of electrons is also 46.

Determine the Number of Neutrons

The atomic mass number is 108 (this is the superscripted number), which is the sum of protons and neutrons. Subtract the number of protons from the atomic mass number: \(108 - 46 = 62\) So, there are 62 neutrons in the atom.

Determine the Ratio of Atomic Masses

The atomic mass of \(^{108}\)Pd is given as 107.90389 u and the atomic mass of \(^{12}_{6}\mathrm{H}\) is exactly 12 u (by definition). So, the ratio of the atomic mass of \(^{108}\)Pd to \(^{12}_{6}\mathrm{H}\) is \( \frac{107.90389}{12} \)

Key concepts

Atomic Mass

Atomic mass refers to the mass of an atom, typically expressed in atomic mass units (u). It is a key characteristic that helps identify and differentiate elements. The atomic mass is mainly determined by the massive particles within the nucleus, namely protons and neutrons.

Atoms consist of three primary subatomic particles: protons, neutrons, and electrons. Of these, protons and neutrons contribute the majority of the mass. Electrons are much lighter and contribute negligibly to the atomic mass. Therefore, atomic mass can be roughly calculated as the sum of the protons and neutrons present in an atom.

However, it is important to note that atomic masses found on periodic tables are averaged values reflecting the various isotopes of an element. Isotopes have the same number of protons but different numbers of neutrons, which means they have different atomic masses despite being the same element. For instance, in the element Pallasium ( ^{108}Pd), its specific mass has been recorded as 107.90389 u.

Protons and Neutrons

Protons and neutrons reside in the nucleus of an atom and together define many of the atom's properties.

**Protons**: - Positively charged particles. - The number of protons in an atom defines the chemical element. - For example, palladium ( Pd) with an atomic number of 46 always contains 46 protons.

**Neutrons**: - Electrically neutral, meaning they have no charge. - Contribute to the atomic mass but not the charge of the atom. - Their number can vary in atoms of the same element, leading to different isotopes.

In any atom, protons and neutrons are tightly packed in the nucleus. The sum of the number of protons and neutrons is called the atomic mass number, or nucleon number. This number helps to identify the particular variation or isotope of the element. For instance, in ^{108}Pd, out of the total atomic mass number of 108, 46 are protons and the remaining 62 are neutrons.

Isotopes

Isotopes are varieties of a given element that have the same number of protons but differ in the number of neutrons they contain. This results in different atomic masses while maintaining the same atomic number.

All atoms of an element share the same number of protons, which is what defines the element's identity. However, the number of neutrons can differ among atoms of the same element. These differing versions are called isotopes.

Consider palladium ( Pd) as an example: - The isotope ^{108}Pd has 46 protons and 62 neutrons, given the total atomic number of 108. - Another isotope, like ^{105}Pd, would have the same number of protons (46) but only 59 neutrons.

Isotopes are important in chemistry and medicine for various applications, such as radioactive dating and medical imaging, where the different properties of isotopes can be exploited to provide valuable information or therapeutic effects.