Question

Consider an atom of \(^{63} \mathrm{Cu}\) (a) How many protons, neutrons, and electrons does this atom contain? (b) What is the symbol of the ion obtained by removing two electrons from 63 \(\mathrm{Cu} ?(\mathbf{c})\) What is the symbol for the isotope of \(^{63} \mathrm{Cu}\) that possesses 36 neutrons?

Short answer

For the given atom of \(^{63}\mathrm{Cu}\): (a) It contains 29 protons, 34 neutrons, and 29 electrons. (b) After removing two electrons, the symbol of the ion obtained is \(\mathrm{Cu}^{2+}\) or \(\mathrm{Cu^{2+}}\). (c) The symbol of the isotope of \(\mathrm{Cu}\) with 36 neutrons is \(^{65}\mathrm{Cu}\).

Step-by-step solution

Identify the atomic number of Cu

Copper (Cu) is an element found in the periodic table with the atomic number 29. This means that it has 29 protons, which is evident from its symbol, \(\mathrm{Cu}\). Atomic numbers are unique to each element, meaning that no two elements will have the same atomic number.

Determine the number of protons, neutrons, and electrons in the atom for part (a)

The given isotope is \(^{63}\mathrm{Cu}\). The superscript '63' here represents the mass number for this particular isotope of copper. Since the atomic number of copper is 29, we can now determine the number of protons, neutrons, and electrons this isotope has: .number of protons = atomic number = 29 .number of electrons = number of protons (as it is a neutral atom) = 29 .number of neutrons = mass number - atomic number = 63 - 29 = 34 So, the \(^{63}\mathrm{Cu}\) atom contains 29 protons, 34 neutrons, and 29 electrons.

Determine the symbol of the ion obtained by removing two electrons from 63 \(\mathrm{Cu}\) for part (b)

When we remove two electrons from the \(^{63}\mathrm{Cu}\) atom, the number of electrons gets reduced to 27 (29 - 2), while the number of protons and neutrons remains the same. This forms a copper ion with a +2 charge due to the excess two protons. We represent it with the symbol: \(\mathrm{Cu}^{2+}\) or \(\mathrm{Cu^{2+}}\)

Determine the symbol for the isotope of \(^{63}\mathrm{Cu}\) that possesses 36 neutrons for part (c)

Now, we are asked to find the symbol for the isotope of \(\mathrm{Cu}\) that has 36 neutrons. To do this, we first determine its mass number: .mass number = atomic number + number of neutrons = 29 + 36 = 65 The mass number of this isotope of copper is 65 and its symbol is: \(^{65}\mathrm{Cu}\)

Key concepts

Atomic Number

The atomic number is a fundamental property of an element that determines its identity and its position on the periodic table. It is denoted by the letter 'Z' and reflects the number of protons in the nucleus of an atom. Since protons carry a positive charge, the atomic number also represents the charge of the nucleus. For the element copper (Cu), the atomic number is 29, which means that every atom of copper has 29 protons in its nucleus.

Understanding the atomic number is crucial because it is unique to each element. No two elements have the same number of protons, and it is the atomic number that defines the type of element. In learning about isotopes and ions, remembering that the atomic number remains constant is key, because this number does not change, even as isotopes vary in neutrons or ions vary in electrons.

Mass Number

The mass number, represented by the letter 'A', is the total number of protons and neutrons present in an atom's nucleus. Unlike the atomic number, the mass number is not fixed for a given element, since different isotopes of the same element can have varying numbers of neutrons. If you take copper, for instance, a common isotope might be represented as copper-63, written copper-63 (copper-63). This tells us the mass number is 63—indicative of the combined total of 29 protons and 34 neutrons.
The mass number is especially useful when discussing isotopes. An isotope's physical and chemical properties may closely resemble those of other isotopes of the same element, despite differences in mass number. To find the number of neutrons in an atom, subtract the atomic number (the number of protons) from the mass number: mass number - atomic number = neutrons. For example, with copper-63, we calculate 63 - 29 to get 34 neutrons.

Protons, Neutrons, and Electrons

Atoms are made up of three principal subatomic particles: protons, neutrons, and electrons. Protons are positively charged particles found in the nucleus which, along with neutral neutrons, make up the majority of an atom's mass. The number of protons (atomic number) determines the element's identity. Electrons are negatively charged particles and orbit the nucleus in various energy levels.

The balance between protons and electrons generally dictates an atom's charge. In a neutral atom, the number of protons and electrons is equal, cancelling out their charges and resulting in no net electrical charge. However, when an atom gains or loses electrons, it becomes an ion; it has a net charge due to the imbalance. For instance, removing two electrons from a neutral copper atom gives us a Cu²⁺ ion, indicating a positive charge with two more protons than electrons.

Copper Isotopes

Isotopes are different forms of the same element that have the same number of protons but different numbers of neutrons in their nuclei, leading to differences in mass number. Copper has two stable isotopes found in nature: copper-63 (copper-63) and copper-65 (copper-65), with mass numbers of 63 and 65, respectively. Hence, while both isotopes have 29 protons, copper-63 has 34 neutrons and copper-65 has 36 neutrons.

Isotopes are designated by their elemental symbol followed by the mass number. When comparing isotopes, such as in the exercise where copper-63 with 36 neutrons was mentioned, we must first add the number of protons to the number of neutrons to determine the new mass number. With 29 protons plus 36 neutrons, we get copper-65, a different isotope from copper-63.