Question

How many electrons, protons, and neutrons are there in each of the following atoms? (a) magnesium- \(24,^{24} \mathrm{Mg}\) (b) tin-119, \(^{119} \mathrm{Sn}\) (c) thorium- \(232,^{232}\) Th (d) carbon-13, \(^{13} \mathrm{C}\) (e) copper-63, \(^{63}\) Cu (f) bismuth- \(205,^{205} \mathrm{Bi}\)

Short answer

Protons, electrons, and neutrons for these atoms are: (a) 12, 12, 12; (b) 50, 50, 69; (c) 90, 90, 142; (d) 6, 6, 7; (e) 29, 29, 34; (f) 83, 83, 122.

Step-by-step solution

Understanding Atomic Notation

In atomic notation, an atom is represented as \( ^A_Z \text{Element} \), where \( A \) is the mass number (total number of protons and neutrons) and \( Z \) is the atomic number (number of protons). Electrons in a neutral atom equal the number of protons.

Finding Details for Magnesium-24

For magnesium-24, \( ^{24}_{12} \text{Mg} \):- Protons \( = 12 \) (atomic number of Mg)- Electrons \( = 12 \) (same as protons in a neutral atom)- Neutrons \( = 24 - 12 = 12 \) (mass number minus atomic number)

Finding Details for Tin-119

For tin-119, \( ^{119}_{50} \text{Sn} \):- Protons \( = 50 \) (atomic number of Sn)- Electrons \( = 50 \)- Neutrons \( = 119 - 50 = 69 \)

Finding Details for Thorium-232

For thorium-232, \( ^{232}_{90} \text{Th} \):- Protons \( = 90 \) (atomic number of Th)- Electrons \( = 90 \)- Neutrons \( = 232 - 90 = 142 \)

Finding Details for Carbon-13

For carbon-13, \( ^{13}_{6} \text{C} \):- Protons \( = 6 \) (atomic number of C)- Electrons \( = 6 \)- Neutrons \( = 13 - 6 = 7 \)

Finding Details for Copper-63

For copper-63, \( ^{63}_{29} \text{Cu} \):- Protons \( = 29 \) (atomic number of Cu)- Electrons \( = 29 \)- Neutrons \( = 63 - 29 = 34 \)

Finding Details for Bismuth-205

For bismuth-205, \( ^{205}_{83} \text{Bi} \):- Protons \( = 83 \) (atomic number of Bi)- Electrons \( = 83 \)- Neutrons \( = 205 - 83 = 122 \)

Key concepts

Protons and Neutrons

In the atomic structure, protons and neutrons are subatomic particles found in the nucleus of an atom. Protons are positively charged particles, while neutrons have no charge and are considered neutral. Together, they contribute to the mass of an atom.

• Protons determine the atomic number of an element, which is unique for each element and decides its position in the periodic table.
• Neutrons contribute to the stability of an atom. Different numbers of neutrons in the nucleus can lead to different isotopes of the same element.

The number of protons and neutrons in an atom is reflected in its mass number, denoted as "A" in atomic notation. For example, a carbon atom with 6 protons and 7 neutrons has a mass number of 13. In summary, understanding protons and neutrons is essential for determining the identity and possible isotopes of an element.

Atomic Notation

Atomic notation is a way to denote an atom using symbols that convey its important characteristics. The notation is usually written as \( ^A_Z \text{Element} \), where \( A \) is the mass number (total number of protons and neutrons) and \( Z \) is the atomic number (number of protons). This notation helps easily identify different atoms and their characteristics.

• The atomic number \( Z \) is crucial because it defines the type of element. For instance, carbon has an atomic number of 6, meaning each carbon atom has 6 protons.
• The mass number \( A \) indicates the sum of protons and neutrons. For example, magnesium-24 is noted as \( ^{24}_{12} \text{Mg} \), showing 12 protons and 12 neutrons.

Atomic notation provides a concise way to present detailed information about an atom's components, making it easier to understand and compare different atoms.

Isotopes

Isotopes are different forms of the same element, having the same number of protons but varying numbers of neutrons. This results in different mass numbers for the isotopes. For example, carbon has two stable isotopes, carbon-12 and carbon-13.

• The chemical properties of isotopes of an element are typically very similar because they have the same number of electrons and protons.
• However, isotopes can have different nuclear properties, which can affect their stability.
• Isotopes are often used in scientific applications such as radiocarbon dating or medical imaging.

To identify an isotope, both its atomic number and mass number are necessary. Different isotopes have different mass numbers but the same atomic number. This distinction helps in understanding variations within the same element.

Neutral Atoms

A neutral atom is an atom where the number of protons equals the number of electrons, resulting in no overall charge. The balance of positive and negative charges ensures the atom is electrically neutral.

• For example, a neutral atom of magnesium (\( ^{24}_{12} \text{Mg} \)) has 12 protons and 12 electrons.
• This balance is important because it determines the way atoms interact chemically with one another. An imbalance would lead to an ion, which is either positively or negatively charged.

Understanding neutral atoms is crucial for grasping basic chemistry concepts such as bonding and reactivity, since most elements in nature appear in their neutral form. This balance allows atoms to form stable molecules and compounds.